VOLVO
CEM-1A5D - Communication with the electronic throttle module (ETM). Signal missing
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
4 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007)
Show models by year and engine (10)
- Volvo S60 (2001–2009)2001–2004
- Volvo S60 (2001–2009)2005Engine B5244SG, B5244SG2 only
- Volvo S60 (2001–2009)2006–2008Engine B5244SG only
- Volvo S80 (1999–2006)1999–2004
- Volvo S80 (1999–2006)2005Engine B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2006Engine B5244SG only
- Volvo V70 (2000–2008)2000–2004
- Volvo V70 (2000–2008)2005Engine B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2006–2008Engine B5244SG only
- Volvo V70 XC / XC70 (2001–2007)2001–2004
What does this fault code mean?
The central electronic module (CEM) has lost communication with the electronic throttle module (ETM) and sets this code. The fault lies in the communication, not in the CEM, so the CEM should not be replaced. Without contact with the ETM the engine runs at a substitute speed, so the accelerator pedal may feel sluggish or not respond.
Possible causes
- The ETM is not getting power
- The ground wire to the ETM is broken
- Contact resistance in the connections
- Broken CAN wiring to the ETM
- Wrong ETM for this car, for example a used module with different software or hardware
- A common CAN network fault if several communication faults are stored at the same time
What you can do
- 1Switch the ignition on and check that the MIL in the instrument panel goes out. If it stays lit, the fault is probably still present
- 2Check the ETM fuse. If it has blown, replace it once. If it blows again, use a multimeter to check the wire after it has no contact with ground.
- 3Check that the connector to the throttle module is seated and not corroded, chafed or damaged. Check that the ground point on the engine block is clean and tight
- 4Use a multimeter to check that the ground wire between the ETM and the engine block has no break. With a diagnostic tool, read the module ID
- 5After the work, clear the code and road-test the car to check that the pedal responds normally
Symptoms you may notice3
- The accelerator pedal responds poorly
- The accelerator pedal does not respond
- The malfunction indicator lamp (MIL) is lit
What the fault can affect1
- A substitute engine speed is set, which affects throttle response
General guidance for car owners. Diagnosis on the car can point to a different cause.