What does fault code ECM-P056100 mean?

Diagnostic fault code details for ECM-P056100 (Volvo S60 (2011–), Volvo S80 (2007–), Volvo V40 (2013–)). Repair service at OBD Tuning.

VOLVO

ECM-P056100 - System Voltage Unstable. General Failure Information. No sub type information

System

Engine Control Module (ECM)

Volvo models this fault code applies to

Applies to the following models:

8 models

S60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V70 (2008–), XC60 (2009–), XC70 (2008–)

Show models by year and engine (8)

What does this fault code mean?

The fault is stored when the engine control module (ECM) finds that the system voltage is unstable while the engine is running. The causes are most often the connections to the battery and the system relay, or the earth connection to the battery. The charging system and the battery can also be the cause.

Possible causes

Loose earth connection to the battery
Contact resistance in the connections to the system relay
Contact resistance in the connections to the battery
Damaged power supply or charging system
Damaged battery

What you can do

1Check that the battery terminals and cable lugs are tight and free of oxidation
2Check the earth connection to the battery for looseness and oxidation
3Check the contact block of the system relay for contact resistance and oxidation
4If a generator fault code is stored, troubleshoot that code first
5If you have diagnostic equipment: read the system voltage in live data with the engine running and check whether the value changes erratically
6If the connections are clean and tight, have a workshop check the battery and charging system with diagnostic equipment

Symptoms you may notice1

No noticeable symptoms for the driver

What the fault can affect1

Glow plug heating for the diesel engine is disabled

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