U0027 Diagnostic Trouble Code

U0027 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 U0027 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
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

Possible Causes :

Defective ECU strategies or components will prevent proper regeneration
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.
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. Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition.

Process Tips

Diagnostic trouble code U0027 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 U0027.

Fortunately, U0027 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0027 Trouble Code For Specific Cars

U0027 Maserati Levante Transmission Fluid Pressure Sensor/Switch F Circuit
U0027 Suzuki Hayabusa Metering Oil Pump Temperature Sensor Circuit Malfunction
U0027 Bristol 407 Crank / Cam Sensor Range / Performance
U0027 Rambler Ambassador Fuel Temperature Sensor B Circuit Malfunction
U0027 Dodge Sprinter Ignition Start Circuit Failure
U0027 Maybach Exelero Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Failure
U0027 Porsche Carrera Gt Fuel Pulse In Range But Higher Than Expected