VOLVO
ECM-A048 - Speed signal, rear wheel pair. Defective signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
3 modelsC30 (2007–2013), S40 (2004–2013), V50 (2004–2013)
What does this fault code mean?
The engine control module calculates vehicle speed using, among other things, the wheel sensors on the rear wheels. If the calculated speed does not match the vehicle speed available on the CAN network, the code is set. Because the comparison is made while driving, the fault mainly shows when the car is moving.
Possible causes
- A fault in the brake control module (BCM)
- CAN-related fault codes in the central electronic module (CEM)
What you can do
- 1Read the fault codes in the BCM first, then in the CEM
- 2Check that the connectors to the rear wheel sensors are fully seated and free from dirt and oxidation, and look for chafing in the wiring
- 3Fault-trace and remedy the faults in the brake control module and the CAN-related codes in the CEM first; this code cannot be cleared until they have been remedied and cleared
- 4The brake control module and the wheel sensors are part of the braking system, so do not work on them yourself; have a workshop check them
Symptoms you may notice3
- Automatic engine start and stop does not work while driving
- Automatic engine start and stop does not work at idle
- Autostart does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.