What does fault code ECM-0850 mean?

Diagnostic fault code details for ECM-0850 (Volvo C30 (2007–2013), Volvo C30 (2007–2013), Volvo C30 (2007–2013)). Repair service at OBD Tuning.

VOLVO

ECM-0850 - Park / Neutral Switch Input Circuit

System

Engine Control Module (ECM)

Volvo models this fault code applies to

Applies to the following models:

3 models

C30 (2007–2013), S40 (2004–2013), V50 (2004–2013)

Show models by year and engine (9)

What does this fault code mean?

The ECM compares the signal from the gear position sensor for positions P and N with the same position sent over CAN by the transmission control module (TCM). If they differ, the code is set, and the ECM then uses the CAN signal instead.

Possible causes

Short circuit to earth or supply voltage in the signal wire
Open circuit in the signal wire
Fault in the transmission control module (TCM), which should be checked first

What you can do

1Check that the fuses are intact in the fuse boxes
2Check the connectors at the gear position sensor and the transmission control module for looseness, contact resistance and oxidation
3If you have a diagnostic tool, read the fault codes in the transmission control module and remedy them first
4With the ignition off, use a multimeter to check the signal wire for an open circuit and for a short to earth or supply voltage
5If the fault remains, have a workshop decide which part needs replacing

Symptoms you may notice1

The starter motor does not turn

What the fault can affect1

The ECM uses the signal received over CAN instead

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