How to change OBD protocol

[reflexsa]

Firstly thanks for this, it was exactly what I was searching for.
I just wanted to ask how/where do I change the OBD protocol? I need to select "const char ISO_15765_11_BIT_500_KBAUD = '6';" to work reliably with my vehicle.
Apologies for the silly question!

[PowerBroker2]

The elm should automatically find and use the best protocol, but if you want to specify it yourself, you can do so in the begin() function:

ELMduino/src/ELMduino.cpp

Lines 3 to 23 in e81f308

	/*
	bool ELM327::begin(Stream &stream, const bool& debug, const uint16_t& timeout, const char& protocol, const uint16_t& payloadLen, const byte& dataTimeout)
	Description:
	------------
	* Constructor for the ELM327 Class; initializes ELM327
	Inputs:
	-------
	* Stream &stream - Reference to Serial port connected to ELM327
	* bool debug - Specify whether or not to print debug statements to "Serial"
	* uint16_t timeout - Time in ms to wait for a query response
	* char protocol - Protocol ID to specify the ELM327 to communicate with the ECU over
	* uint16_t payloadLen - Maximum number of bytes expected to be returned by the ELM327 after a query
	* byte dataTimeout - Number of ms to wait after receiving data before the ELM327 will
	return the data - see https://www.elmelectronics.com/help/obd/tips/#UnderstandingOBD
	Return:
	-------
	* bool - Whether or not the ELM327 was properly initialized
	*/
	bool ELM327::begin(Stream &stream, const bool &debug, const uint16_t &timeout, const char &protocol, const uint16_t &payloadLen, const byte &dataTimeout)

[reflexsa]

Thank you. For some reason when using my adapter with Torque for example I will get an 'engine check light' unless I specify the protocol. The actual error is communication to the gearbox so it seems that is somehow interfered with.
So would I just change the "const char &protocol" to 6 in the below?
bool ELM327::begin(Stream &stream, const bool &debug, const uint16_t &timeout, const char &protocol, const uint16_t &payloadLen, const byte &dataTimeout)

to:
bool ELM327::begin(Stream &stream, const bool &debug, const uint16_t &timeout, 6, const uint16_t &payloadLen, const byte &dataTimeout)

[PowerBroker2]

You would have to add the argument in the sketch kind of like this:

myELM327.begin(ELM_PORT, true, 2000, ISO_15765_11_BIT_500_KBAUD);

[reflexsa]

Thank you. I see, that does make sense. I'm hoping this will resolve my other issue where I just have a recurring response after the initial AT commands #241

[jimwhitelaw]

Fixed in version 3.3.0.