What does fault code CEM-DE01 mean?

Diagnostic fault code details for CEM-DE01 (Volvo C30 (2007–2013), Volvo C30 Electric (2011–2013), Volvo C70 (2006–2013)). Repair service at OBD Tuning.

VOLVO

CEM-DE01 - Communication with the brake control module (BCM). Signal missing

System

Central Electronic Module (CEM)

Volvo models this fault code applies to

Applies to the following models:

5 models

C30 (2007–2013), C30 Electric (2011–2013), C70 (2006–2013), S40 (2004–2013), V50 (2004–2013)

Show models by year and engine (5)

What does this fault code mean?

The central module has lost contact with the brake control module (BCM) over the CAN network. ABS then does not work, the ABS warning lamp may come on, and the starter motor may not work. The cause may be a missing voltage supply to the brake control module, contact resistance at connections, a break in the CAN wiring, or a module that is not intended for this car.

Possible causes

No voltage supply to the brake control module (BCM)
Contact resistance at the connections
Open circuit in the wiring to the CAN high-speed network for the brake control module (BCM)
The brake module does not belong to this car, e.g. a used unit with other software

What you can do

1Check the brake module fuses in the engine bay box, per the manual. If one is blown, check the circuit after it for a short to ground first
2Check that the earth point of the brake control module is clean and tight, and use a multimeter to check that the earth wire has no break
3With a diagnostic tool, try to read the brake control module ID. If it can be read, CAN communication is probably fine and the fault may be intermittent
4Do not replace the central module when CAN fault codes are present, since they point to a communication fault in the network
5The brake control module runs the ABS: with no ABS function, the brakes have no anti-lock protection, so brake early and have a workshop check the brake system promptly

Symptoms you may notice4

The starter motor does not work
The ABS warning lamp comes on
No ABS function
A message in the display

What the fault can affect1

No ABS function, so the brakes work but without anti-lock protection

General guidance for car owners. Diagnosis on the car can point to a different cause.