Diagnostic Procedure

The role of the Can and Driver Information Module (CDM) is the overall control of the communication network and a number of DTCs which indicate the fault. In case of communication problems the fault may exist in another part of the communication network.

1. Turn Ignition on. Read off DTCs in the CDM. Check if there are DTCs on the communication network.
2. If there DTCs stored for the communication network in the CDM, fault-trace according to the DTCs. If there are no communication DTCs stored, go to next step.
3. Check the connector on the Electronic Throttle Module (ETM). Check for contact resistance and oxidation. In particular, check terminals 3 (CAN H) and 4 (CAN L), 5 (ground) and 6 (voltage). For wire colors, see ENGINE PERFORMANCE WIRING DIAGRAMS article.
4. Check the connector on the ECM. Check for contact resistance and oxidation. In particular check terminals A37 (CAN H) and A55 (CAN L). For wire colors, see ENGINE PERFORMANCE WIRING DIAGRAMS article.
5. In particular, check the wiring, pins and terminals for damage. Check that they are properly inserted into the connector. Check that the cable is properly connected to the pin or terminal.
6. Check the CAN H cable between ETM terminal No. 3 (white wire) and ECM A37. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage. Check the CAN L cable between ETM terminal No. 4 and ECM A55. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
7. Check the voltage supply cable between ETM terminal No. 6 and system relay terminal No. 3 (87). See Figure. See ENGINE PERFORMANCE WIRING DIAGRAMS article. Check for an open-circuit.
   NOTE: With the ignition on, the voltage must be approximately battery voltage between ETM terminal No. 6 and ground.
8. Check the ground lead between ETM terminal No. 5 and the engine block. Check for an open-circuit. Check for a short-circuit to supply voltage.
9. If the DTC persists, despite the above checks and remedies, replace the Electronic Throttle Module (ETM). See REMOVAL, OVERHAUL & INSTALLATION - EXCEPT S40 & V40 article.
   NOTE: A new ETM is delivered without software. For the ETM to function after replacement, it must be programmed using a Volvo factory scan tool, or equivalent aftermarket scan tool.
10. Read out fault memory again after repair is complete. If DTC is no longer present, repair is complete.