U20A4 Mercedes A 200 OBD Code

OBD/2 U20A4 error code description and symptoms.

HO2S Sensor Circuit Malfunction (HO2S-11) During testing the HO2S Heaters are checked for opens/shorts and excessive current draw.
The test fails when current draw exceeds a calibrated limit and/or an open or short is detected. Short to VPWR in harness or HO2S. Water in harness connector. Open VPWR circuit. Open GND circuit. Low battery voltage. Corrosion or poor mating terminals and wiring Damaged HO2S heater. Damaged PCM.

One example of this would be when an automatic vehicle in placed in gear. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. Note that the idle air control valve is closed by the PCM when the throttle plate is opened to prevent excess air from entering the engine.

U20A4 Mercedes A 200 Error Code Repair Process :

If your air bag driver circuit open - loop #2 check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system U20A4 and engine control unit are in charge of monitoring a bunch of different air bag driver circuit open - loop #2, and if they get a reading that's a little out of whack, up pops the check engine light.

Common Causes of Mercedes A 200 U20A4 OBD2 Code

A common cause of code U20A4 is the failure of Air Bag Driver Circuit Open - Loop #2, but there are several other possible causes as well, such as ;

Exhaust tube
Faulty Camshaft Position Sensor
Insufficient cylinders compression
Spark plugs may be faulty

U20A4 is a kind of Network Trouble Code

U-code indicates that engine communication errors and shows lost communication with engine parts.U-Codes are fairly straight forward, given all of the articles and technical publications that have been written regarding these problematic codes. In most cases, it just comes down to identifying the module that isn't communicating with the other modules on the CAN bus line for whatever reason.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

About Us | Contact | Privacy

U20A4 Mercedes A 200 OBD Code

U20A4 Mercedes A 200 Error Code Repair Process :

Common Causes of Mercedes A 200 U20A4 OBD2 Code

U20A4 code for other Mercedes cars