U3963 Mercedes-benz E Class OBD Code

OBD/2 U3963 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.

U3963 Mercedes-benz E Class Error Code Repair Process :

If your fuel temperature sensor #1 circuit short to ground 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 U3963 and engine control unit are in charge of monitoring a bunch of different fuel temperature sensor #1 circuit short to ground, and if they get a reading that's a little out of whack, up pops the check engine light.

Common Causes of Mercedes-benz E Class U3963 OBD2 Code

A common cause of code U3963 is the failure of Fuel Temperature Sensor #1 Circuit Short to Ground, but there are several other possible causes as well, such as ;

Exhaust tube
Engine Control Module (ECM)
Intake Valve Timing Control Solenoid Valve circuit poor electrical connection
Internal electrical failures in actuator motors/solenoids.

U3963 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.

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U3963 Mercedes-benz E Class OBD Code

U3963 Mercedes-benz E Class Error Code Repair Process :

Common Causes of Mercedes-benz E Class U3963 OBD2 Code

U3963 code for other Mercedes-benz cars