VOLVO
ECM-U007400 - Control module communication bus "B" Off. General Failure Information. No sub type information
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
8 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V70 (2008–), XC60 (2009–), XC70 (2008–)
Show models by year and engine (8)
- Volvo S60 (2011–)2014–2015Engine B4204T10, B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo S80 (2007–)2014–2015Engine B4204T11, B4204T12, B4204T15, D4204T5 only
- Volvo V40 (2013–)2015Engine B4204T11, D4204T14 only
- Volvo V40 Cross Country (2013–)2015Engine B4204T11, D4204T14 only
- Volvo V60 (2011–)2014–2015Engine B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo V70 (2008–)2014–2015Engine B4204T11, D4204T5 only
- Volvo XC60 (2009–)2014–2015Engine B4204T10, B4204T11, B4204T12, B4204T15, B4204T9, D4204T5 only
- Volvo XC70 (2008–)2014–2015Engine B4204T11, D4204T5 only
What does this fault code mean?
The engine control module (ECM) has stopped communicating on CAN network B and switched itself off (bus-off). The code is set when the module detects that CAN communication is blocked by a serious disturbance, and then the other control modules cannot reach it.
Possible causes
- Contact resistance or oxidation in the connections
- Open circuit in one of the CAN wires
- Short circuit between the CAN wires
- Internal fault in the ECM
- Internal fault in another control module on the same part of the CAN network
What you can do
- 1Read the code with a diagnostic tool and see whether it is active or only stored
- 2Look at the codes in the other control modules, since they may show that they have also lost contact with the network
- 3Check the connections at the engine control module and at other control modules on the same network for contact resistance and oxidation
- 4Use a multimeter to check that the CAN wires have no break and no short to each other
- 5Have a workshop determine whether the engine control module or another control module on the network is communicating wrongly
Symptoms you may notice4
- Check engine light comes on or behaves abnormally
- The engine lacks power, especially when pulling away from standstill
- The engine hesitates or surges on acceleration and at steady speed
- Red warning symbol and text message in the display
What the fault can affect2
- The engine control module stops communicating on the CAN network and switches itself off
- The engine control module stays off until the voltage supply has been broken, and makes new attempts to communicate when the voltage is connected again
General guidance for car owners. Diagnosis on the car can point to a different cause.