VOLVO
CEM-DE6E - Communication with the transmission control module (TCM). Signal missing
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
5 modelsC30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The CEM has lost contact with the transmission control module (TCM). As a result some gear changes do not happen, the malfunction indicator may light and a message can appear in the display. The fault is most often caused by supply, earth or a connector at the TCM.
Possible causes
- No supply to the TCM
- Open circuit in the earth wire to the TCM
- Contact resistance in the connections
- Open circuit in the LS-CAN wires to the TCM
- The TCM does not suit the car, for example a used module with other software or hardware
What you can do
- 1Switch the ignition on and check that the light on the gear selector panel comes on. If it does not, the TCM probably has no supply
- 2Check the TCM fuse in the engine bay fuse box and the TCM fuse in the CEM. If one has blown, check its circuit for a short to earth before replacing it
- 3Use a multimeter to check that the wires from the fuse box and from the CEM to the TCM have no break
- 4Check the TCM earth wire and earth point for play and oxidation
- 5With a diagnostic tool, read the TCM ID. If it reads, the communication is probably fine and the fault may be intermittent
- 6After the repair, clear the fault code and road test to check that gear changes work and the fault does not return
Symptoms you may notice3
- Gear changes do not happen
- The malfunction indicator lamp is lit
- A message appears in the text display
What the fault can affect1
- A substitute gear is engaged instead of the selected gear
General guidance for car owners. Diagnosis on the car can point to a different cause.