What does fault code ECM-P250287 mean?

Diagnostic fault code details for ECM-P250287 (Volvo S60 (2011–), Volvo S80 (2007–), Volvo S80 (2007–)). Repair service at OBD Tuning.

VOLVO

ECM-P250287 - Charging System Voltage. Bus Signal / Message Failures. Missing message

System

Engine Control Module (ECM)

Volvo models this fault code applies to

Applies to the following models:

3 models

S60 (2011–), S80 (2007–), V70 (2008–)

Show models by year and engine (9)

What does this fault code mean?

Two control units, the ECM and the alternator control module (ACM, the charge regulator), talk over a LIN wire. The code is stored when the engine control module detects interference in that communication. The fault may lie in the wiring, in the connectors or in either of the control modules.

Possible causes

Contact resistance or oxidation in the connections
Short-circuit between the LIN wires
Open circuit in one of the LIN wires
Internal fault in another control module on the same part of the LIN network
Damaged alternator control module (ACM, charge regulator)
A generator whose charge regulator is not made for LIN communication has been fitted

What you can do

1If the generator has been replaced, check that it is intended for LIN communication, since a generator of the wrong type can cause this code
2Inspect the plug on the ACM for contact resistance and oxidation; clean and remedy it if needed
3Check the LIN wire for chafing. Use a multimeter to check that it has no open circuit and is not short-circuited to ground or plus
4If the fault remains after these checks, have a workshop try a new alternator control module

Symptoms you may notice1

The "Generator not charging" warning lamp lights with the engine running

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