U0988 Diagnostic Trouble Code

U0988 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 U0988 diagnostic trouble code may include:

Misfire
Misfire
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Reduction in engine performance, especially at low RPM levels

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.
Fuel with a large percentage of sulfur will clog the DPF quickly

Repair Processes :

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. 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. 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 U0988 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 U0988.

Fortunately, U0988 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0988 Trouble Code For Specific Cars

U0988 Fitch Phoenix Left Rear Sensor Circuit Failure
U0988 Seat Ibiza Injector Control Pressure Above Expected Level
U0988 Nissan Rogue Crankshaft Position Sensor B Circuit Intermittent
U0988 Ford C-max Ii Low A/C Cycling Period
U0988 Volkswagen Iltis Right Front Center Sensor Circuit Fault
U0988 Ford Ranchero Mirror Passenger Left Circuit Failure
U0988 Lancia Fulvia Speed Wheel Sensor Rear Center Input Short Circuit To Battery