C0631 Diagnostic Trouble Code

C0631 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a C0631 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Reduction in engine performance, especially at low RPM levels

Possible Causes :

Dirty air cleaner element Damaged DPF
A plugged converter will cause of host of driveability problems as well as set this code. A severely plugged converter will result in the inability to increase rpm when under load. Look for a code such as P0421 -- catalytic converter efficiency below threshold if the converter indicating a faulty converter.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code C0631 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C0631.

Fortunately, C0631 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0631 Trouble Code For Specific Cars

C0631 Alta 2-litre Air Bag Passenger Pressure Switch Circuit Open
C0631 Peugeot H2o Engine Coolant Level Switch Circuit Failure, GEM
C0631 Bentley R-type Battery Temp out of Range
C0631 Italdesign Buron SCP (J1850) Invalid or Missing Data for Window Wiper / Washer
C0631 Nissan 1600 Child Seat Detection Circuit Short To Battery
C0631 Renault Trafic 3 HO2S Heater Control Circuit High (Bank 2 Sensor 1)
C0631 Citroen Tub Fuel Pump Speed Primary Circuit Malfunction