C0397 Diagnostic Trouble Code

C0397 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 C0397 diagnostic trouble code may include:

Excessive exhaust leak
Hesitation upon acceleration
Malfunction Indicator Lamp (MIL) illuminated
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly

Possible Causes :

Defective ECU strategies or components will prevent proper regeneration
The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. Now, clear the codes and test-drive the vehicle to see if the code is reset. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code C0397 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 C0397.

Fortunately, C0397 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0397 Trouble Code For Specific Cars

C0397 Subaru Xv MAF Sensor In Range But Higher Than Expected
C0397 Triumph Tr Pedal Correlation PDS2 and HPDS
C0397 Bmw R-nine T Clutch position ckt short to ground
C0397 Alfa Romeo 1900 ABS Power Relay Output Short Circuit To Battery
C0397 Alfa Romeo 90 Accelerometer Rear Circuit Short To Battery
C0397 Volkswagen 1200 RCNT Solenoid Circuit Malfunction
C0397 Fiat 128 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)