VOLVO
ECM-U003700 - Vehicle Communication Bus B. General Failure Information. No sub type information
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
1 modelV60 (2011–)
Show models by year and engine (2)
What does this fault code mean?
The engine control module (ECM) monitors the communication with the other control modules on the sensor CAN. The code is set when it detects faulty communication, and the fault may lie in the wiring or in the connectors.
Possible causes
- Contact resistance or oxidation in the connectors
- Open circuit in one of the CAN network wires
- One of the CAN wires is shorted to ground
- One of the CAN wires is shorted to voltage
- The CAN wires are shorted to each other
What you can do
- 1Read the code with a diagnostic tool and check whether it is active or only stored
- 2Check the connectors to the engine control module and to other control modules on the sensor CAN for contact resistance and oxidation
- 3Use a multimeter to check that the CAN wires have no break, no contact with ground or voltage, and no contact with each other
- 4Gently move the wiring harness with the ignition on and see whether the code follows
- 5Have a workshop check the load on the CAN network and which control module is disturbing the communication, since the fault does not always lie in the engine control module
Symptoms you may notice1
- Red warning symbol and text message in the display
General guidance for car owners. Diagnosis on the car can point to a different cause.