What does fault code TCM-P086088 mean?

Diagnostic fault code details for TCM-P086088 (Volvo S60 (2011–), Volvo S80 (2007–), Volvo V40 (2013–)). Repair service at OBD Tuning.

VOLVO

TCM-P086088 - Gear Shift Control Module "A" Communication Circuit. Bus Signal / Message Failures. Bus off

System

Transmission Control Module (TCM)

Volvo models this fault code applies to

Applies to the following models:

9 models

S60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)

Show models by year and engine (9)

What does this fault code mean?

The code is set when the signal from the gear selector control module (GSM) is missing in the transmission control module (TCM). The TCM then uses a default value instead of the signal. The cause may be a break in the LIN wire or an internal fault in the selector control module.

Possible causes

Break in the LIN wire
Internal fault in the gear selector control module (GSM)

What you can do

1If you have a diagnostic tool: press the brake, move the selector to M and check whether the status changes in live data.
2Use a multimeter to check that the LIN wire has continuity without a break between the selector and the gearbox.
3Check that the connectors in the LIN wire are secure and not corroded.
4Have a workshop check the LIN bus and, if needed, replace the selector control module (GSM).
5After a control module is replaced, the workshop must download new software.

Symptoms you may notice4

Message and yellow warning symbol
The gear indicator in the gauges does not work
No manual gear changes
Low battery voltage warning

What the fault can affect1

The TCM uses a default value for the signal

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