U20A4 Diagnostic Trouble Code

U20A4 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 U20A4 diagnostic trouble code may include:

Lack of power
Faulty O2 Sensor
Poor acceleration
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

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.
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

Repair Processes :

Now, clear the codes and test-drive the vehicle to see if the code is reset. 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.

Process Tips

Diagnostic trouble code U20A4 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 U20A4.

Fortunately, U20A4 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U20A4 Trouble Code For Specific Cars

U20A4 Isuzu D-max SCP (J1850) Invalid or Missing Data for Telltales
U20A4 Holden Caprice Pedal Position Rearward Switch Circuit Short to Battery
U20A4 Durkopp 24 Hp Immobilizer to PCM Signal Error
U20A4 Citroen Karin
U20A4 Isuzu Kb250
U20A4 Berkeley Foursome B-pillar Power Sliding Door Open/Close Switch Input Ckt Short to Gnd
U20A4 Nissan 110 Charging System Fault