U0135 Diagnostic Trouble Code

U0135 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 U0135 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 :

It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem. 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. Look at the plug wires to make sure they are not burnt or laying on the exhaust.

Process Tips

Diagnostic trouble code U0135 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 U0135.

Fortunately, U0135 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0135 Trouble Code For Specific Cars

U0135 Opel Filo Dim Panel Decrease Input Circuit Open
U0135 Vauxhall Wyvern Pressure Transducer Main / Primary signal Faulted
U0135 Mercedes Gle Class Accelerometer Rear Circuit Signal Is Not Sensed
U0135 Pontiac Fiero Exhaust Pressure Sensor Malfunction
U0135 Toyota Bb O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
U0135 Land Rover Series Iii Switch Test Signal Failure
U0135 Mazda Demio 3 Transmission Transfer Case Shift Motor Short Circuit To Ground