VOLVO
CEM-DF15 - CAN-H, high speed network. Signal too low
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
10 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), S60 (2001–2009), S80 (1999–2006), V50 (2004–2013), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (10)
- Volvo C30 (2007–2013)2007–2013
- Volvo C30 Electric (2011–2013)2011–2013
- Volvo C70 (2006–2013)2006–2013
- Volvo S40 (2004–2013)2004–2012
- Volvo S60 (2001–2009)2005–2009
- Volvo S80 (1999–2006)2005–2006
- Volvo V50 (2004–2013)2004–2012
- Volvo V70 (2000–2008)2005–2008
- Volvo V70 XC / XC70 (2001–2007)2005–2007
- Volvo XC90 (2003–)2005–2015
What does this fault code mean?
The CEM detects that CAN H in the high speed network has been shorted to earth, so the signal becomes too low. The engine may then stall or fail to start. The fault most often lies in the high speed network wiring.
Possible causes
- Short to earth on the CAN H wire in the high speed network
What you can do
- 1If the engine will not start, check the battery and that the starter turns the engine over first. That rules out simpler causes
- 2Note when the engine stalls, for example at certain movements or after a while. This gives a clue to where the cable is damaged
- 3With a diagnostic tool, read the fault codes from all control modules and see which ones show communication faults
- 4Use a multimeter to check that the CAN H wire has no contact with earth or the body along its length
- 5Check the connectors in the high speed network for loose connections, corrosion and moisture
- 6An engine that stalls while driving is a safety problem. Do not drive far with the fault present, and have a workshop repair it promptly
Symptoms you may notice4
- The engine does not start
- The engine stalls, including while driving
- The malfunction indicator lamp is lit
- A message appears in the text display
General guidance for car owners. Diagnosis on the car can point to a different cause.