What does fault code ECM-0400 mean?

Diagnostic fault code details for ECM-0400 (Volvo C30 (2007–2013), Volvo C30 (2007–2013), Volvo C30 (2007–2013)). Repair service at OBD Tuning.

VOLVO

ECM-0400 - EGR control. Flow fault

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 (13)

What does this fault code mean?

The engine control module (ECM) compares the pressure in the intake pipe with the EGR control active against the pressure with it inactive. If the pressure changes too little, the control module interprets this as an EGR flow fault. The causes may be an EGR valve stuck open, a blocked exhaust system, or damaged control to the valve.

Possible causes

EGR valve stuck in the open position
Blocked exhaust system
Damaged control to the EGR valve

What you can do

1Read out the fault code, erase it and road-test to see whether it returns
2Look for damage and signs of blockage in the exhaust system, such as a pinched or deformed section
3Switch off the ignition and check the connector and wiring to the EGR valve for looseness, corrosion and chafing
4If you have a diagnostic tool, read the EGR valve position in live data at idle and see whether the value changes when the valve is controlled
5If the fault remains, have a workshop with diagnostic equipment check the EGR valve and its control

Symptoms you may notice2

The malfunction indicator lamp (MIL) is lit
Uneven idle

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