What does fault code ECM-U210786 mean?

Diagnostic fault code details for ECM-U210786 (Volvo S60 (2011–), Volvo S60 (2011–), Volvo S80 (2007–)). Repair service at OBD Tuning.

VOLVO

ECM-U210786 - Collision Mitigation By Braking. Bus Signal / Message Failures. Signal invalid

System

Engine Control Module (ECM)

Volvo models this fault code applies to

Applies to the following models:

5 models

S60 (2011–), S80 (2007–), V60 (2011–), V70 (2008–), XC60 (2009–)

Show models by year and engine (12)

What does this fault code mean?

The engine control module (ECM) gets signals from the forward sensing module (FSM) and the central electronic module (CEM) and applies braking help when a collision threatens. The code is set when one of the input signals from the FSM is lost. The code indicates that communication between the FSM and the engine control module is not working properly.

Possible causes

The fault is in the forward sensing module (FSM)
Open circuit in the communication cable
Communication cable short-circuited to ground or to voltage
Contact resistance or oxidation in the connections
Open circuit or short-circuit in the connections

What you can do

1Read the fault codes in the engine control module. If any of ECM-U012088, ECM-U000188, ECM-U1A1400, ECM-U000108 or ECM-U000100 is stored, check it first.
2Read the fault codes in the FSM. If it has a code of its own, that is likely the root cause and the engine control module code is a follow-on fault.
3Check that the connectors between the engine control module and the FSM are secure and clean, and look for chafed wiring.
4If the code returns, have a workshop troubleshoot the FSM with diagnostic equipment, as this requires measurement.

Symptoms you may notice2

The check engine lamp lights up or behaves abnormally
Warning symbol and message in the display

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