CAN communication

ECM (Engine Control Module) sends out and receives the following signals via the network:

Can and Driver information Module (CDM)

Is the "main computer" in the network and sends on required information to other modules.

It also controls diagnostic communication by connecting the data link connector (DLC) to the network for programming/downloading and reading off diagnostic trouble codes (DTCs) and parameters.

Transmission Control Module (TCM)

The following signals are sent out on the network from the engine control module (ECM) and taken up by the TCM:

Engine load
Throttle opening
Acknowledgment of torque limiting

The following signals are sent out on the network from the Transmission Control Module (TCM) and taken up by the ECM:

Torque limiting request stage I and II
Request to operate the malfunction indicator lamp (MIL)
Constant idle speed compensation (P/N position) signal

Electronic Throttle Module (ETM)

The following signals are sent out on the network from the electronic throttle module and taken up by the engine control module (ECM):

Provides information about current throttle position
Request via engine control module (ECM) to the CAN and Driver module to light the electronic throttle system lamp
faults discovered in the electronic throttle module are stored as diagnostic trouble codes (DTCs) in the Engine Control Module (ECM)

Anti-lock Braking System (ABS)

The following signals are sent out on the network from the ABS and taken up by the ECM:

Vehicle speed signal, (goes via the CAN and diver module first)

The ABS module continuously sends out the largest differences between the wheel sensor signals on the network, approximately 50 times per second. Using these values the engine control module (ECM) can determine if any misfiring is due to the nature of the road or if there are genuine interruptions in the engine control module. Because of this the accelerometer is not required.

Data Link Connector (DLC)

The request (initiation) when reprogramming and downloading new software takes place via the data link connector (DLC) (pin 7,C-line) to the Can and Driver information Module which closes two internal relays and thereby opens communication with the network.