### Install py-obdii via pip

Source: https://py-obdii.readthedocs.io/en/latest

Install the library using pip to get started with vehicle communication.

```bash
pip install py-obdii
```

--------------------------------

### Install ELM327-Emulator

Source: https://py-obdii.readthedocs.io/en/latest

Install the library with simulation capabilities using the sim extra.

```bash
pip install py-obdii[sim]
```

--------------------------------

### Connect and Query OBDII Data

Source: https://py-obdii.readthedocs.io/en/latest

Example showing how to scan for available ports, establish a connection, and query both adapter firmware and engine speed.

```python
from obdii import Connection, at_commands, commands
from obdii.utils.scan import scan_ports

# Find first available OBDII device connected via serial
ports = scan_ports(return_first=True)
if not ports:
    raise ValueError("No OBDII devices found.")

# Connect to the adapter
with Connection(ports[0]) as conn:
    # Query adapter firmware version
    version = conn.query(at_commands.VERSION_ID)
    print(f"Version: {version.value}")

    # Query vehicle's engine speed (rpm)
    response = conn.query(commands.ENGINE_SPEED)
    print(f"Engine Speed: {response.value} {response.units}")
```

--------------------------------

### Template substitution example

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Demonstrates how to define a Template with placeholders and perform substitution using either keyword or positional arguments.

```python
t = Template("AT {a:str} {b:int} {c:hex4} {d}")
r = t.substitute(a=1, b=2.2, c=3, d="four")
# or
r = t.substitute(1, 2.2, 3, "four")

>>> r
"AT 1 2 0003 four"
```

--------------------------------

### Start ELM327-Emulator

Source: https://py-obdii.readthedocs.io/en/latest

Run the emulator module. Replace REPLACE_WITH_PORT with the actual serial port identifier.

```bash
python -m elm -p "REPLACE_WITH_PORT" -s car --baudrate 38400
```

--------------------------------

### SupportedPIDS.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Initializes a SupportedPIDS object with a base PID. The base PID is the starting point for parsing supported PIDs.

```APIDOC
## SupportedPIDS.__init__

### Description
Initializes a SupportedPIDS object with a base PID. The base PID is the starting point for parsing supported PIDs.

### Method
Constructor

### Parameters
- **base_pid** (int) - Required - The base PID from which the support bits start.

### Example
```python
supported_pids = SupportedPIDS(0x01)
```
```

--------------------------------

### Parse supported PIDs with SupportedPIDS

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Demonstrates parsing a 4-byte response to identify supported PIDs starting from a base PID.

```python
unparsed = [190, 31, 168, 19]
# 190       31        168       19
# B    E    1    F    A    8    1    3
# 1011 1110 0001 1111 1010 1000 0001 0011

supported_pids = SupportedPIDS(0x01)
result = supported_pids(unparsed)

>>> result
[0x01, 0x03, 0x04, 0x05, 0x06, 0x07, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x13, 0x15, 0x1C, 0x1F, 0x20]
```

--------------------------------

### AT FI - FAST_INIT

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Performs a fast initiation sequence for ISO 14230-4 KWP, requires protocol 5 to be active.

```APIDOC
## AT FI

### Description
Performs a fast initiation sequence for ISO 14230-4 KWP, requires protocol 5 to be active.

### Command
AT FI
```

--------------------------------

### Connection.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Initializes connection settings and optionally auto-connects to the device.

```APIDOC
## Connection.__init__

### Description
Initializes connection settings and optionally auto-connects to the device.

### Method
Constructor

### Parameters
- **transport** (str | Tuple[str, str | int] | TransportBase) - Required - Can be a string for serial ports (e.g., "COM5", "/dev/ttyUSB0", "/dev/rfcomm0"), a tuple for network transports (e.g., ("<hostname>", <port>)), or an instance of a TransportBase subclass.
- **protocol** (Protocol) - Optional - The protocol to use for communication. Defaults to Protocol.AUTO.
- **auto_connect** (bool) - Optional - If True, connect to the adapter immediately. Defaults to True.
- **smart_query** (bool) - Optional - If True, send repeat command when the same command is issued again. Defaults to False.
- **early_return** (bool) - Optional - If True, the ELM327 will return immediately after sending the specified number of responses. Works only with ELM327 v1.3 and later. Defaults to False.
- **log_handler** (logging.Handler | None) - Optional - Custom log handler for the logger.
- **log_formatter** (logging.Formatter) - Optional - Formatter to use with the given log handler.
- **log_level** (int) - Optional - Logging level for the logger.
- **log_root** (bool) - Optional - Whether to set up the root logger. Defaults to False.
- **kwargs** (dict) - Optional - Additional keyword arguments forwarded to the transport's constructor.

### Returns
None
```

--------------------------------

### Connection.__enter__()

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Support usage as a context manager.

```APIDOC
## __enter__()

### Description
Support usage as a context manager.

### Returns
- Connection: The connection instance itself.
```

--------------------------------

### Connection.connect

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Establishes a connection to the device using the configured transport and runs the initialization sequence.

```APIDOC
## Connection.connect

### Description
Establishes a connection to the device using the configured transport and runs the initialization sequence.

### Method
connect

### Parameters
- **kwargs** - Optional - Additional keyword arguments forwarded to the transport's connect method.

### Returns
None
```

--------------------------------

### Command.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Initializes a Command instance with mode, PID, expected bytes, value ranges, units, and an optional resolver.

```APIDOC
## Command.__init__

### Description
Initializes a Command instance with the specified mode, PID, expected bytes, value ranges, units, and resolver.

### Method
Constructor

### Parameters
- **mode** (Mode | int | str) - Required - Command mode to be used.
- **pid** (Template | int | str) - Required - Command PID (Parameter Identifier) to be used.
- **expected_bytes** (int | Iterable[int]) - Optional - The number of bytes expected in the response. Defaults to 0.
- **min_values** (int | float | Iterable[int | float] | None) - Optional - Minimum valid values for the command's parameters.
- **max_values** (int | float | Iterable[int | float] | None) - Optional - Maximum valid values for the command's parameters.
- **units** (str | Iterable[str] | None) - Optional - The units for the command's response.
- **resolver** (Callable[[...], T] | None) - Optional - A resolver function for custom response handling.

### Returns
None
```

--------------------------------

### AT IIA {hh} - SET_ISO_INIT_ADDR

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the destination address for the ISO 9141-2 or ISO 14230-4 slow (5 baud) initiation sequence, default is $33.

```APIDOC
## AT IIA {hh}

### Description
Sets the destination address for the ISO 9141-2 or ISO 14230-4 slow (5 baud) initiation sequence, default is $33.

### Command
AT IIA {hh}

### Parameters
- **hh** (hex byte) - Required - Destination address for initiation.
```

--------------------------------

### ModeAT.PROG_SUMMARY

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Displays a summary of all Programmable Parameters, showing their values and whether they are enabled.

```APIDOC
## ModeAT.PROG_SUMMARY

### Description
Display a summary of all Programmable Parameters, showing their values and whether they are enabled.

### Command
ModeAT.PROG_SUMMARY

### Usage
```python
from obdii.modes import ModeAT
ModeAT.PROG_SUMMARY
```

### Notes
- The command is "PPS".
```

--------------------------------

### AT SI - SLOW_INIT

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Performs a slow initiation sequence for ISO 9141-2 or ISO 14230-4 KWP (5 baud), requires protocol 3 or 4 to be active.

```APIDOC
## AT SI

### Description
Perform a slow initiation sequence for ISO 9141-2 or ISO 14230-4 KWP (5 baud), requires protocol 3 or 4 to be active.

### Command
AT SI
```

--------------------------------

### AT KW1 - KEY_WORD_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables standard key word checking during initiation sequences (default).

```APIDOC
## AT KW1

### Description
Enable standard key word checking during initiation sequences (default).

### Command
AT KW1
```

--------------------------------

### Command.build

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Builds the query to be sent to the ELM327 device as a byte string.

```APIDOC
## Command.build

### Description
Builds the query to be sent to the ELM327 device as a byte string. The ELM327 is case-insensitive, ignores spaces and all control characters.

### Method
build

### Parameters
- **early_return** (bool) - Optional - Whether to include the early return digit in the command. If True, appends a hex digit representing the expected number of responses. Defaults to False.

### Returns
- **bytes** - The formatted query as a byte string, ready to be sent to the ELM327 device.

### Raises
- **ValueError** - If the PID is a Template, meaning the command has likely not been formatted.
```

--------------------------------

### MultiFormula.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Initializes a MultiFormula object with multiple expression strings. Variable names are converted to uppercase.

```APIDOC
## MultiFormula.__init__

### Description
Initializes a MultiFormula object with multiple expression strings. Variable names are converted to uppercase.

### Method
Constructor

### Parameters
- **expressions** (str) - Required - Expression strings to evaluate.

### Example
```python
engine_torque = MultiFormula("A-125", "B-125", "C-125", "D-125", "E-125")
```
```

--------------------------------

### Command.__call__

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Formats the command with provided positional or keyword arguments and returns a new Command instance.

```APIDOC
## Command.__call__

### Description
Formats the command with the provided positional or keyword arguments, returning a new Command instance with the formatted PID.

### Method
Callable

### Parameters
- **args** (Any) - Optional - Positional arguments corresponding to placeholders in the command's PID template.
- **kwargs** (Any) - Optional - Keyword arguments corresponding to placeholders in the command's PID template.

### Returns
- **Command[T]** - A new Command instance with the formatted PID.
```

--------------------------------

### ModeAT.PROG_PARAMS_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables all Programmable Parameters at the same time.

```APIDOC
## ModeAT.PROG_PARAMS_ON

### Description
Enable all Programmable Parameters at the same time.

### Command
ModeAT.PROG_PARAMS_ON

### Usage
```python
from obdii.modes import ModeAT
ModeAT.PROG_PARAMS_ON
```

### Notes
- The command is "PP FF ON".
```

--------------------------------

### AT IB 10 - SET_BAUDRATE_10400

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the ISO 9141-2 and ISO 14230-4 baud rate to the default of 10400.

```APIDOC
## AT IB 10

### Description
Sets the ISO 9141-2 and ISO 14230-4 baud rate to the default of 10400.

### Command
AT IB 10
```

--------------------------------

### AT IB 48 - SET_BAUDRATE_4800

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the ISO 9141-2 and ISO 14230-4 baud rate to 4800.

```APIDOC
## AT IB 48

### Description
Sets the ISO 9141-2 and ISO 14230-4 baud rate to 4800.

### Command
AT IB 48
```

--------------------------------

### AT TP {h} - TRY_PROTOCOL

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Attempts to use protocol h without saving it to EEPROM.

```APIDOC
## AT TP {h}

### Description
Attempts to use protocol h without saving it to EEPROM.

### Command
AT TP {h}

### Parameters
- **h** (hex digit) - Required - Protocol number to try.
```

--------------------------------

### Formula.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Initializes a Formula object with a mathematical expression string. Variable names are converted to uppercase.

```APIDOC
## Formula.__init__

### Description
Initializes a Formula object with a given expression string. Variable names are converted to uppercase.

### Method
Constructor

### Parameters
- **expression** (str) - Required - The expression string to evaluate.

### Example
```python
formula = Formula("(256*A+B)/4")
```
```

--------------------------------

### ModeAT.VERSION_ID

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Displays the device identification string and firmware version.

```APIDOC
## ModeAT.VERSION_ID

### Description
Display the device identification string and firmware version.

### Command
ModeAT.VERSION_ID

### Usage
```python
from obdii.modes import ModeAT
ModeAT.VERSION_ID
```

### Notes
- The command is "AT I".
```

--------------------------------

### Template.substitute()

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Substitutes placeholders in the template with provided values. Accepts either positional or keyword arguments, but not both. Returns the resulting string.

```APIDOC
## Template.substitute()

### Description
Substitutes the placeholders in the template with the provided values. The substitution must use either positional or keyword arguments, not both.

### Method
substitute

### Signature
substitute(*args, **kwargs) -> str

### Parameters
- *args (Any) - Positional arguments corresponding to the placeholders in the template.
- **kwargs (Any) - Keyword arguments corresponding to the placeholders in the template.

### Returns
- str: The template string with placeholders replaced by the provided values.

### Example
```python
t = Template("AT {a:str} {b:int} {c:hex4} {d}")
r = t.substitute(a=1, b=2.2, c=3, d="four")
# or
r = t.substitute(1, 2.2, 3, "four")
```
```

--------------------------------

### AT KW - KEY_WORDS

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Displays the two key word bytes received from the ECU during the initiation sequence.

```APIDOC
## AT KW

### Description
Display the two key word bytes received from the ECU during the initiation sequence.

### Command
AT KW
```

--------------------------------

### scan_transports(candidates, transport_cls, probe=..., return_first=False, **kwargs)

Source: https://py-obdii.readthedocs.io/en/latest/api/utils.html

Attempts to detect working transports from a list of candidate configurations. It instantiates the given transport class for each candidate, sends a probe byte sequence, and returns a list of valid transports. If return_first is True, it stops after the first valid transport is found.

```APIDOC
## scan_transports(candidates, transport_cls, probe=..., return_first=False, **kwargs)

### Description
Attempt to detect working transports from a list of candidates.

### Parameters
- **candidates** (List[Dict[str, Any]]) - Required - List of transport configuration dictionaries. For example, for serial: [{"port": "COM3"}], for WiFi: [{"address": "192.168.0.10", "port": 35000}]
- **transport_cls** (Type[TransportBase]) - Required - Transport class to instantiate for probing (e.g., TransportSerial, TransportSocket).
- **probe** (bytes) - Optional - Byte sequence to send to test the transport. Defaults to at_commands.VERSION_ID.build().
- **return_first** (bool) - Optional - If True, stop scanning and return after the first valid transport is found.
- **kwargs** (dict) - Optional - Additional keyword arguments forwarded to the transport's connect method.

### Returns
List[TransportBase] - List of working transport instances.
```

--------------------------------

### AT TP A{h} - TRY_PROTOCOL_AUTO

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Attempts to use protocol h without saving it to EEPROM while enabling automatic detection on failure.

```APIDOC
## AT TP A{h}

### Description
Attempts to use protocol h without saving it to EEPROM while enabling automatic detection on failure.

### Command
AT TP A{h}

### Parameters
- **h** (hex digit) - Required - Protocol number to try.
```

--------------------------------

### Connection.query(command)

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Sends a command and waits for the response.

```APIDOC
## query(command)

### Description
Send a command and wait for the response.

### Parameters
- **command** (Command) - Required - Command to send.

### Returns
- Response: Parsed response from the adapter.
```

--------------------------------

### AT IB 96 - SET_BAUDRATE_9600

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the ISO 9141-2 and ISO 14230-4 baud rate to 9600.

```APIDOC
## AT IB 96

### Description
Sets the ISO 9141-2 and ISO 14230-4 baud rate to 9600.

### Command
AT IB 96
```

--------------------------------

### ModeAT.DESCRIPTION

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Displays the device description string of the ELM327.

```APIDOC
## ModeAT.DESCRIPTION

### Description
Display the device description string of the ELM327.

### Command
ModeAT.DESCRIPTION

### Usage
```python
from obdii.modes import ModeAT
ModeAT.DESCRIPTION
```

### Notes
- The command is "AT @1".
```

--------------------------------

### AT IB 15 - SET_BAUDRATE_15625

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the ISO 9141-2 and ISO 14230-4 baud rate to 15625.

```APIDOC
## AT IB 15

### Description
Sets the ISO 9141-2 and ISO 14230-4 baud rate to 15625.

### Command
AT IB 15
```

--------------------------------

### ModeAT.LOWPOWER

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enters low power standby mode, reducing power consumption until awakened by activity or reset.

```APIDOC
## ModeAT.LOWPOWER

### Description
Enter low power standby mode, reducing power consumption until awakened by activity or reset.

### Command
ModeAT.LOWPOWER

### Usage
```python
from obdii.modes import ModeAT
ModeAT.LOWPOWER
```

### Notes
- The command is "AT LP".
```

--------------------------------

### AT IB 12 - SET_BAUDRATE_12500

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the ISO 9141-2 and ISO 14230-4 baud rate to 12500.

```APIDOC
## AT IB 12

### Description
Sets the ISO 9141-2 and ISO 14230-4 baud rate to 12500.

### Command
AT IB 12
```

--------------------------------

### ModeAT.RESET

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Performs a complete hardware reset, restoring all settings and the default baud rate.

```APIDOC
## ModeAT.RESET

### Description
Performs a complete hardware reset, restoring all settings and the default baud rate.

### Command
ModeAT.RESET

### Usage
```python
from obdii.modes import ModeAT
ModeAT.RESET
```

### Notes
- The command is "AT Z".
```

--------------------------------

### ModeAT.RESET_SOFT

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Performs a software reset restoring defaults while preserving baud rate settings.

```APIDOC
## ModeAT.RESET_SOFT

### Description
Perform a software reset restoring defaults while preserving baud rate settings.

### Command
ModeAT.RESET_SOFT

### Usage
```python
from obdii.modes import ModeAT
ModeAT.RESET_SOFT
```

### Notes
- The command is "AT WS".
```

--------------------------------

### AT SS - STANDARD_SEARCH

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Uses the SAE J1978 standard protocol search sequence for initiating connections.

```APIDOC
## AT SS

### Description
Use the SAE J1978 standard protocol search sequence for initiating connections.

### Command
AT SS
```

--------------------------------

### AT KW0 - KEY_WORD_OFF

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Disables key word checking, allowing initiation to proceed even if key word values are non-standard.

```APIDOC
## AT KW0

### Description
Disable key word checking, allowing initiation to proceed even if key word values are non-standard.

### Command
AT KW0
```

--------------------------------

### AT CAF1 - FORMAT_AUTO_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables CAN automatic formatting, automatically handling PCI bytes, padding, and simplifying CAN send and receive data.

```APIDOC
## AT CAF1

### Description
Enable CAN automatic formatting, automatically handling PCI bytes, padding, and simplifying CAN send and receive data.

### Command
AT CAF1
```

--------------------------------

### DTC.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Initializes a DTC object with a raw DTC code string. The DTC is parsed into its components: category, scope, system, and descriptor.

```APIDOC
## DTC.__init__

### Description
Initializes a DTC object with a raw DTC code string. The DTC is parsed into its components: category, scope, system, and descriptor.

### Method
Constructor

### Parameters
- **raw** (str) - Required - The raw DTC code string, e.g. "U0158".

### Attributes
- **code** (str) - Full DTC code, e.g. "U0158".
- **category** (Category) - DTC category, e.g. Category.NETWORK.
- **scope** (Scope) - DTC scope, e.g. Scope.GENERIC.
- **system** (System) - DTC system, e.g. System.FUEL_AIR_METERING.
- **descriptor** (str) - DTC descriptor, e.g. "58".

### Example
```python
dtc = DTC("U0158")
```
```

--------------------------------

### scan_network(return_first=True, **kwargs)

Source: https://py-obdii.readthedocs.io/en/latest/api/utils.html

Scans common WiFi endpoints for ELM327 compatible devices. Returns a list of working network transports, or the first one if return_first is True.

```APIDOC
## scan_network(return_first=True, **kwargs)

### Description
Scan common WiFi endpoints for ELM327 compatible devices.

### Parameters
- **return_first** (bool) - Optional - If True, stop scanning and return after the first valid transport is found. Defaults to True.
- **kwargs** (dict) - Optional - Additional keyword arguments forwarded to the transport's connect method.

### Returns
List[TransportBase] - List of working network transport instances.
```

--------------------------------

### AT SW {hh} - SET_WAKEUP

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets the periodic wakeup messages interval to hh * 20 ms, keeps the ECU connection active, only supported for protocols 3, 4, and 5.

```APIDOC
## AT SW {hh}

### Description
Set the periodic wakeup messages interval to hh * 20 ms, keeps the ECU connection active, only supported for protocols 3, 4, and 5.

### Command
AT SW {hh}

### Parameters
- **hh** (hex byte) - Required - Wakeup interval multiplier, actual interval is hh * 20 ms.
```

--------------------------------

### scan_ports(return_first=True, **kwargs)

Source: https://py-obdii.readthedocs.io/en/latest/api/utils.html

Scans available serial ports for ELM327 compatible devices. Returns a list of working serial transports, or the first one if return_first is True.

```APIDOC
## scan_ports(return_first=True, **kwargs)

### Description
Scan available serial ports for ELM327 compatible devices.

### Parameters
- **return_first** (bool) - Optional - If True, stop scanning and return after the first valid transport is found. Defaults to True.
- **kwargs** (dict) - Optional - Additional keyword arguments forwarded to the transport's connect method.

### Returns
List[TransportBase] - List of working serial transport instances.
```

--------------------------------

### Map data bytes to enumerated values with EnumeratedPIDS

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Demonstrates mapping raw byte values to human-readable strings using a dictionary mapping.

```python
unparsed = [0, 0]

fuel_system_status = EnumeratedPIDS(
    {
        0: "The motor is off",
        1: "Open loop due to insufficient engine temperature",
        2: "Closed loop, using oxygen sensor feedback to determine fuel mix",
        4: "Open loop due to engine load OR fuel cut due to deceleration",
        8: "Open loop due to system failure",
        16: "Closed loop, using at least one oxygen sensor but there is a fault in the feedback system",
    }
)
result = fuel_system_status(unparsed)

>>> result
[(0, "The motor is off"), (0, "The motor is off")]
```

--------------------------------

### ModeAT.PROG_PARAM_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables the specified hh Programmable Parameter, allowing its assigned value to override the factory default.

```APIDOC
## ModeAT.PROG_PARAM_ON

### Description
Enable the specified hh Programmable Parameter, allowing its assigned value to override the factory default.

### Command
ModeAT.PROG_PARAM_ON

### Parameters
- **hh** (hexadecimal) - Required - The programmable parameter number.

### Usage
```python
from obdii.modes import ModeAT
ModeAT.PROG_PARAM_ON
```

### Notes
- The command template is "PP {hh} ON".
```

--------------------------------

### ModeAT.RESET_DEFAULTS

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Restores all settings, including protocol, headers, filters, masks and timers to their factory default values.

```APIDOC
## ModeAT.RESET_DEFAULTS

### Description
Restore all settings, including protocol, headers, filters, masks and timers to their factory default values.

### Command
ModeAT.RESET_DEFAULTS

### Usage
```python
from obdii.modes import ModeAT
ModeAT.RESET_DEFAULTS
```

### Notes
- The command is "AT D".
```

--------------------------------

### ModeAT.ECHO_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables echoing of characters received on the RS232 port back to the host computer.

```APIDOC
## ModeAT.ECHO_ON

### Description
Enable echoing of characters received on the RS232 port back to the host computer.

### Command
ModeAT.ECHO_ON

### Usage
```python
from obdii.modes import ModeAT
ModeAT.ECHO_ON
```

### Notes
- The command is "AT E1".
```

--------------------------------

### Mode09.IN_USE_PERF_TRACKING_COMPRESSION_IGNITION

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_09.html

Command to retrieve in-use performance tracking for compression ignition vehicles.

```APIDOC
## Mode09.IN_USE_PERF_TRACKING_COMPRESSION_IGNITION

### Description
Command to retrieve in-use performance tracking for compression ignition vehicles.

### Command
Mode09.IN_USE_PERF_TRACKING_COMPRESSION_IGNITION

### Parameters
None

### Response
Returns in-use performance tracking data for compression ignition vehicles.
```

--------------------------------

### AT WM {xxxxxxxxxxxx} - WAKEUP_MESSAGE

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Overrides the default periodic wakeup message, accepts 1 to 6 bytes.

```APIDOC
## AT WM {xxxxxxxxxxxx}

### Description
Override the default periodic wakeup message, accepts 1 to 6 bytes.

### Command
AT WM {xxxxxxxxxxxx}

### Parameters
- **xxxxxxxxxxxx** (hex string) - Required - Wakeup message bytes, 1 to 6 bytes.
```

--------------------------------

### EnumeratedPIDS.__init__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Initializes an EnumeratedPIDS object with a mapping dictionary. The mapping maps byte values to their corresponding enumerated meanings.

```APIDOC
## EnumeratedPIDS.__init__

### Description
Initializes an EnumeratedPIDS object with a mapping dictionary. The mapping maps byte values to their corresponding enumerated meanings.

### Method
Constructor

### Parameters
- **mapping** (Dict[Union[int, Iterable[int]], Any]) - Required - A dictionary mapping byte values to their corresponding enumerated meanings.

### Example
```python
fuel_system_status = EnumeratedPIDS({
    0: "The motor is off",
    1: "Open loop due to insufficient engine temperature",
    2: "Closed loop, using oxygen sensor feedback to determine fuel mix",
    4: "Open loop due to engine load OR fuel cut due to deceleration",
    8: "Open loop due to system failure",
    16: "Closed loop, using at least one oxygen sensor but there is a fault in the feedback system",
})
```
```

--------------------------------

### AT C1 - CONFIRMATION_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables confirmation of CAN message transmission errors, requires an ELM327 >= 2.3.

```APIDOC
## AT C1

### Description
Enable confirmation of CAN message transmission errors, requires an ELM327 >= 2.3.

### Command
AT C1
```

--------------------------------

### Evaluate multiple formulas with MultiFormula

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Demonstrates using the MultiFormula class to apply multiple expressions to a single list of unparsed data.

```python
# 143 (dec) -> A
# 125 (dec) -> B
# 149 (dec) -> C
# 128 (dec) -> D
# 111 (dec) -> E
unparsed = [143, 125, 149, 128, 111]

engine_torque = MultiFormula("A-125", "B-125", "C-125", "D-125", "E-125")
result = engine_torque(unparsed)

>>> result
[18, 0, 24, 3, -14]
```

--------------------------------

### ProtocolConnectionError

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised when no supported protocol is detected. Verify vehicle ignition status, compatibility, and connections.

```APIDOC
## ProtocolConnectionError

### Description
No supported protocol detected. Verify vehicle ignition status, compatibility, and connections.

### Constructor
`ProtocolConnectionError(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the error.

### Attributes
- `pattern` (bytes | None) - `b'UNABLE TO CONNECT'`

### Inherits
- `ResponseError`

```

--------------------------------

### Connection.__exit__(exc_type, exc_value, traceback)

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Close the connection when exiting the context.

```APIDOC
## __exit__(exc_type, exc_value, traceback)

### Description
Close the connection when exiting the context.

### Parameters
- **exc_type** (Type[BaseException] | None) - Required - Exception type.
- **exc_value** (BaseException | None) - Required - Exception value.
- **traceback** (TracebackType | None) - Required - Traceback.

### Returns
- None
```

--------------------------------

### ModeAT.READ_VOLTAGE

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Reads the current input voltage at pin 2 and converts it to a decimal string.

```APIDOC
## ModeAT.READ_VOLTAGE

### Description
Read the current input voltage at pin 2 and converts it to a decimal string.

### Command
ModeAT.READ_VOLTAGE

### Usage
```python
from obdii.modes import ModeAT
ModeAT.READ_VOLTAGE
```

### Notes
- The command is "RV".
```

--------------------------------

### CanError

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised when the CAN system had difficulty initializing, sending, or receiving.

```APIDOC
## CanError

### Description
The CAN system had difficulty initializing, sending, or receiving.

### Constructor
`CanError(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the error.

### Attributes
- `pattern` (bytes | None) - `b'CAN ERROR'`

### Inherits
- `ResponseError`

```

--------------------------------

### Connection.wait_for_response(context)

Source: https://py-obdii.readthedocs.io/en/latest/api/core.html

Waits for a raw response from the transport and parses it using the protocol handler.

```APIDOC
## wait_for_response(context)

### Description
Wait for a raw response from the transport and parses it using the protocol handler.

### Parameters
- **context** (Context) - Required - Context to use for parsing.

### Returns
- Response: Parsed response or raw fallback response.
```

--------------------------------

### ModeAT.REPEAT

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Repeats the last AT or OBD command performed.

```APIDOC
## ModeAT.REPEAT

### Description
Repeat the last AT or OBD command performed.

### Command
ModeAT.REPEAT

### Usage
```python
from obdii.modes import ModeAT
ModeAT.REPEAT
```

### Notes
- This command repeats the last AT or OBD command.
```

--------------------------------

### ProtocolKWP.to_frames()

Source: https://py-obdii.readthedocs.io/en/latest/api/protocols.html

Parses a list of raw ELM327 lines into KWPFrame objects. Supports ISO 9141-2 and ISO 14230-4 KWP protocols.

```APIDOC
## ProtocolKWP.to_frames()

### Description
Parses a list of raw ELM327 lines into KWPFrame objects. Supports ISO 9141-2 and ISO 14230-4 KWP protocols.

### Method
Method call

### Endpoint
obdii.protocols.ProtocolKWP.to_frames(lines: List[bytes], context: Context) -> List[Frame]

### Parameters
- **lines** (List[bytes]) - Required - Raw ELM327 lines to parse
- **context** (Context) - Required - Parsing context

### Returns
- **List[Frame]** - Parsed KWP frame objects

### Frame Anatomy
ISO 9141-2 Frame - fixed 3 byte header
```
48 6B 11 41 0C 1F 40 70
|  |  |  |           |
|  |  |  |           +-- checksum: sum of all previous bytes % 256
|  |  |  +-- payload: mode (41) + PID (0C) + data (1F 40)
|  |  +-- source address (sender ECU)
|  +-- target address (receiver)
+-- priority
```

ISO 14230-4 Frame (Standard Header) - length inline within FMT byte
```
84 F1 11 41 0C 1F 44 36
|  |  |  |           |
|  |  |  |           +-- checksum: sum of all previous bytes % 256
|  |  |  +-- payload: mode (41) + PID (0C) + data (1F 44)
|  |  +-- source address (sender ECU)
|  +-- target address (receiver)
+-- FMT: addressing mode (bits 7:6) + payload length (bits 5:0 = 4 bytes)
```

ISO 14230-4 Frame (Extended Header) - length in a separate LEN byte
```
80 F1 11 04 41 0C 1F 44 32
|  |  |  |  |           |
|  |  |  |  |           +-- checksum: sum of all previous bytes % 256
|  |  |  |  +-- payload: mode (41) + PID (0C) + data (1F 44)
|  |  |  +-- LEN: payload length byte (present because bits 5:0 of FMT = 0)
|  |  +-- source address (sender ECU)
|  +-- target address (receiver)
+-- FMT: addressing mode (bits 7:6) + length flag (bits 5:0 = 0)
```
```

--------------------------------

### LowPowerWarning

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised when the ELM327 is entering Low Power mode in 2 seconds. No interruption possible.

```APIDOC
## LowPowerWarning

### Description
The ELM327 is entering Low Power mode in 2 seconds. No interruption possible.

### Constructor
`LowPowerWarning(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the warning.

### Attributes
- `pattern` (bytes | None) - `b'LP ALERT'`

### Inherits
- `ResponseWarning`

```

--------------------------------

### Evaluate a mathematical formula with Formula

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Demonstrates using the Formula class to calculate a result from a list of unparsed integers based on a string expression.

```python
# 11 (dec) -> A
# 64 (dec) -> B
unparsed = [11, 64]

formula = Formula("(256*A+B)/4")
result = formula(unparsed)
# (256 * 11 + 64)/4

>>> result
720.0
```

--------------------------------

### LowVoltageResetWarning

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised to indicate low 5V supply voltage, triggering a reset.

```APIDOC
## LowVoltageResetWarning

### Description
Indicates low 5V supply voltage, triggering a reset.

### Constructor
`LowVoltageResetWarning(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the warning.

### Inherits
- `ResponseWarning`

```

--------------------------------

### SupportedPIDS.__call__

Source: https://py-obdii.readthedocs.io/en/latest/api/parsers.html

Parses supported PIDs from the response data. Returns a list of supported PIDs.

```APIDOC
## SupportedPIDS.__call__

### Description
Parses supported PIDs from the response data. Returns a list of supported PIDs.

### Method
Callable

### Parameters
- **unparsed** (List[int]) - Required - The data to parse.

### Returns
- **List[int]** - List of supported PIDs.

### Example
```python
unparsed = [190, 31, 168, 19]
supported_pids = SupportedPIDS(0x01)
result = supported_pids(unparsed)
# result = [0x01, 0x03, 0x04, 0x05, 0x06, 0x07, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x13, 0x15, 0x1C, 0x1F, 0x20]
```
```

--------------------------------

### SignalFeedbackError

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised when output is energized but input signal is not detected, indicating a possible wiring issue.

```APIDOC
## SignalFeedbackError

### Description
Output energized, but input signal not detected. Possible wiring issue. Verify connections.

### Constructor
`SignalFeedbackError(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the error.

### Attributes
- `pattern` (bytes | None) - `b'FB ERROR'`

### Inherits
- `ResponseError`

```

--------------------------------

### ModeAT.RESTORE_VOLTAGE

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Restores the ELM327 voltage calibration to the original factory setting.

```APIDOC
## ModeAT.RESTORE_VOLTAGE

### Description
Restore the ELM327 voltage calibration to the original factory setting.

### Command
ModeAT.RESTORE_VOLTAGE

### Usage
```python
from obdii.modes import ModeAT
ModeAT.RESTORE_VOLTAGE
```

### Notes
- The command is "CV 0000".
```

--------------------------------

### ModeAT.LINEFEED_ON

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Enables sending of a linefeed character after each carriage return.

```APIDOC
## ModeAT.LINEFEED_ON

### Description
Enable sending of a linefeed character after each carriage return.

### Command
ModeAT.LINEFEED_ON

### Usage
```python
from obdii.modes import ModeAT
ModeAT.LINEFEED_ON
```

### Notes
- The command is "AT L1".
```

--------------------------------

### BufferFullError

Source: https://py-obdii.readthedocs.io/en/latest/api/errors.html

Exception raised when the ELM327's 256-byte buffer is full.

```APIDOC
## BufferFullError

### Description
The ELM327's 256-byte buffer is full.

### Constructor
`BufferFullError(_response: bytes)`

### Parameters
- `_response` (bytes) - Required - The response bytes associated with the error.

### Attributes
- `pattern` (bytes | None) - `b'BUFFER FULL'`

### Inherits
- `ResponseError`

```

--------------------------------

### PROTOCOL_B_BAUDRATE

Source: https://py-obdii.readthedocs.io/en/latest/api/modes/mode_at.html

Sets Protocol B parameters xx and yy, overriding PP 2C and PP 2D values for the next initialization without changing stored programmable parameters.

```APIDOC
## PROTOCOL_B_BAUDRATE

### Description
Sets Protocol B parameters xx and yy, overriding PP 2C and PP 2D values for the next initialization without changing stored programmable parameters.

### Command
AT PB {xx} {yy}

### Parameters
- **xx** (hex) - Required - The first Protocol B parameter.
- **yy** (hex) - Required - The second Protocol B parameter.
```