VOLVO
CEM-DF05 - CAN-H, low 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 low speed network has contact with earth, so the signal becomes too low. Communication between the control modules can then break down, and the gauges, instrument lighting, central locking and remote control may stop working. The fault most often lies in the network wiring.
Possible causes
- Short to earth on the CAN H wire in the low speed network
What you can do
- 1With the ignition on, check whether the gauges and instrument lighting work. Which functions are lost shows which control modules are affected
- 2With a diagnostic tool, read the fault codes from all control modules. Communication faults in several modules point to a shared fault in the network
- 3Use a multimeter to check that the CAN H wire has no contact with earth or the body along its length
- 4Check the connectors on the CAN network for loose connections, corrosion and moisture
- 5Gently flex the cable harness while watching the communication, to see whether the fault disappears or changes
- 6The CEM should not be replaced for a CAN fault unless a workshop has confirmed an internal fault in the CEM
Symptoms you may notice4
- No gauges work
- The instrument lighting does not work
- Locking and unlocking with the remote control does not work
- The central locking does not work at all
General guidance for car owners. Diagnosis on the car can point to a different cause.