CAN Communication

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

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)

Data Link Connector (DLC)

When reprogramming and downloading new software and fault-tracing with Volvo on-board diagnostic (OBD) system the initiation request is transferred from VIDA via data link connector (DLC) pin 7 also called C-link Communication link) to the Can and Driver information Module and closing two internal relays and opening communication with the network.