C1198 Diagnostic Trouble Code

C1198 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 C1198 diagnostic trouble code may include:

Faulty or damaged wiring
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
Poor fuel economy
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

An air leak forward of the DPF will change the sensor readings resulting in the code
Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications. 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.

Process Tips

Diagnostic trouble code C1198 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 C1198.

Fortunately, C1198 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1198 Trouble Code For Specific Cars

C1198 Toyota Bb O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
C1198 Toyota Wish Passenger Seatback Forward Switch Circuit Short to Ground
C1198 Perodua Myvi Dual Alternator Battery Lamp Circuit Malfunction
C1198 Mercedes S 280 Accessory Delay Relay Contact Short To Battery
C1198 Lotus Carlton Torque Converter/Brake Switch B Circuit Malfunction
C1198 Lincoln Ls Throttle Position Sensor Disagreement btwn Sensors
C1198 Jaguar Xj-s Seat Driver Occupied Switch Circuit Failure