OBD Comms not working
Posted: 13 Aug 2023, 16:59
Trying to connect obd reader to an AGG installation; The OBD connector is stashed under the dash (so I assume that this means it is probably connected via the immobiliser?) (as you can tell, this was not my install);
I am seeing 12V on the 12V line, gnd on ground, and 12V on the K-line when the ignition is on.
But the OBD reader is not happy with something - I get the 'failed to communicate' error when it tries to connect.
Connecting a scope to the K-line I can see it being pulled low by the OBD Reader as it tries to set up the initial comms - so things look like they are attempting to work but I'm not getting any comms back from the ECU.
Anyone got anything that I can do to debug?
Should I be seeing 12V on the K-line (with ignition on, but OBD reader not connected)?
Only have 3 wires on the OBD connector - 12V, Chassis gnd and K-line (i.e. no signal ground)
I am doing this with ignition on, but engine not running.
Help please?
I am seeing 12V on the 12V line, gnd on ground, and 12V on the K-line when the ignition is on.
But the OBD reader is not happy with something - I get the 'failed to communicate' error when it tries to connect.
Connecting a scope to the K-line I can see it being pulled low by the OBD Reader as it tries to set up the initial comms - so things look like they are attempting to work but I'm not getting any comms back from the ECU.
Anyone got anything that I can do to debug?
Should I be seeing 12V on the K-line (with ignition on, but OBD reader not connected)?
Only have 3 wires on the OBD connector - 12V, Chassis gnd and K-line (i.e. no signal ground)
I am doing this with ignition on, but engine not running.
Help please?