What does fault code ECM-U000188 mean?

Diagnostic fault code details for ECM-U000188 (Volvo S60 (2011–), Volvo S80 (2007–), Volvo S80 (2007–)). Repair service at OBD Tuning.

VOLVO

ECM-U000188 - High Speed CAN Communication Bus. Bus Signal / Message Failures. Bus off

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?

The engine control module (ECM) has switched itself off on the high speed CAN network, which is called bus-off. The code is set when the module notices that CAN communication is disturbed, either by another control module or by its own messages.

Possible causes

Short circuit between the CAN wires
Open circuit in one of the CAN wires
Internal fault in another control module on the same part of the CAN network
Internal fault in the ECM

What you can do

1Read the codes in other control modules, since another module disturbing the network can set its own codes
2Use a multimeter to check that the CAN wires have no break and no short to each other
3If you have a diagnostic tool: switch the ignition off and on and read whether the code comes back
4Have a workshop determine whether the engine control module or another module on the CAN network is at fault

Symptoms you may notice4

Cruise control does not work at all
The engine bucks on acceleration
The engine shudders heavily after engine braking
Uneven idling

What the fault can affect3

The engine control module switches itself off on the network (bus-off)
The engine control module stays off until the voltage supply has been broken
When the voltage is switched on again, the engine control module makes new attempts to communicate

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