C157B Diagnostic Trouble Code

C157B 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 C157B diagnostic trouble code may include:

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
Faulty or damaged wiring
Hesitation upon acceleration
Rich or lean exhaust

Possible Causes :

Faulty IMRC actuator relay (if equipped)
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

Now, clear the codes and test-drive the vehicle to see if the code is reset. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio.

Process Tips

Diagnostic trouble code C157B 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 C157B.

Fortunately, C157B is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C157B Trouble Code For Specific Cars

C157B Chevrolet Astrovette Driver Door Handle Circuit Failure
C157B Glas 2600 PAD Warning Lamp Circuit Short to Battery
C157B Cadillac Solitaire Dim Panel Increase Input Circuit Short To Ground
C157B Citroen C3 Front Wiper Motor Relay Circuit Short to Vbatt
C157B Cadillac Sts Dimmer switch Circuit Short to Gnd
C157B Talbot-lago America Mirror Passenger Up Circuit Failure
C157B Abarth Monotipo A/C Evaporator Air Temperature Circuit High