VOLVO
ECM-1656 - Control module communication problems. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
Show models by year and engine (6)
- Volvo C30 (2007–2013)2007–2010Engine D4204T only
- Volvo C70 (2006–2013)2008–2010Engine D4204T only
- Volvo S40 (2004–2013)2004–2006Engine D4204T, D4204T2 only
- Volvo S40 (2004–2013)2007–2010Engine D4204T only
- Volvo V50 (2004–2013)2004–2006Engine D4204T, D4204T2 only
- Volvo V50 (2004–2013)2007–2010Engine D4204T only
What does this fault code mean?
The ECM detects a serious disturbance on the CAN bus, which is the shared data link between the car's modules. Communication with it is then blocked, and the fault code is set.
Possible causes
- Contact resistance or oxidation in the terminals
- Open circuit in one of the CAN wires
- Short circuit between the CAN wires
- Fault inside the ECM itself
- Fault inside another module on the same CAN segment
What you can do
- 1First read the fault codes stored in CEM and the other modules. Do not clear this code until those are fixed, since it may be a knock-on fault
- 2Switch off the ignition and check the connectors on the CAN network for contact resistance and oxidation
- 3With a multimeter, check that the CAN wires have no break and are not shorted to each other
- 4If the fault remains after this, have a workshop check the control modules on the CAN network
Symptoms you may notice1
- Warning symbol and a text message in the display
What the fault can affect1
- The engine control module may stay shut off until the power supply is interrupted, then it tries to communicate again
General guidance for car owners. Diagnosis on the car can point to a different cause.