U029F Diagnostic Trouble Code

U029F 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 U029F diagnostic trouble code may include:

Faulty O2 Sensor
Lack of power
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Reduction in engine performance, especially at low RPM levels

Possible Causes :

A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
Some aftermarket accessories and performance modifications
Fuel with a large percentage of sulfur will clog the DPF quickly

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. 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 U029F 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 U029F.

Fortunately, U029F is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U029F Trouble Code For Specific Cars

U029F Bristol 407 Crank / Cam Sensor Range / Performance
U029F Volvo 164
U029F Packard 120 Downstream Heated O2 Sensors Swapped
U029F Mazda Rx-8 A Camshaft Position Actuator Circuit (Bank1)
U029F Belsize 12 Bank 2 Fuel Control Shifted Rich
U029F Mercedes-benz C Class Air Flow Blend Door Driver Circuit Failure
U029F Chevrolet Colorado Driver Sid, Side mount Airbag Circuit Open