U1198 Diagnostic Trouble Code

U1198 is a kind of OBD-II Diagnostic U-Network 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 U1198 diagnostic trouble code may include:

Poor acceleration
Cherry red hot catalytic converter
Possible spark knock (detonation / pre-ignition)
Diminished fuel efficiency

Possible Causes :

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.
Defective ECU strategies or components will prevent proper regeneration
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

Repair Processes :

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. 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. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code U1198 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 U1198.

Fortunately, U1198 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U1198 Trouble Code For Specific Cars

U1198 Jeep Jeepster Seat Driver Rearward Switch Circuit Failure
U1198 Alvis Crested Eagle Air Bag Safing Sensor Output Circuit Short To Ground
U1198 Mercury Villager Air Suspension RF Air Spring Solenoid Output Circuit Failure
U1198 Opel Movano Door Ajar LR Circuit Short To Battery
U1198 Facel Vega Excellence Injection Timing Control Circuit Malfunction
U1198 Mg M-type Air Suspension Warning Lamp Circuit Open
U1198 Benz 27 Boost Calibration Fault