U3963 Mercedes C 240 OBD Code

OBD/2 U3963 error code description and symptoms.

Low Speed Fuel Pump Primary Circuit Malfunction The PCM monitors the low speed fuel pump (LFP) primary circuit output from the PCM.
The test fails if: When the LFP circuit is commanded on (grounded), excessive current draw is detected on the LFP circuit; or when the LFP circuit is commanded off, voltage is not detected on the LFP circuit (the PCM expects to detect VPWR voltage coming through the low speed fuel pump relay coil to the LFP circuit). Open or shorted low fuel pump (LFP) circuit Open VPWR to low speed fuel pump relay Damaged low speed fuel pump relay Damaged PCM An open circuit or short to ground can only be detected with the low speed fuel pump.

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 C 240 Error Code Repair Process :

The scent may U3963 signal oil or coolant leaking from their normally closed-loop systems, or it may indicate dangerous exhaust gases invading your car's interior. Car and truck exhaust contains toxic gases such U3963, so if the inside of your car fuel temperature sensor #1 circuit short to ground as if you were standing behind your car, get out and get it fixed. Fight the urge to take a little nap first. So sleepy. That's the carbon monoxide talking, friends. At least open a window on your way to the shop.

Common Causes of Mercedes C 240 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 ;

EVAP canister or fuel tank leaks
Engine Control Module (ECM)
Faulty TCM or TCM programming
Foreign matter caught in fuel filler cap

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 C 240 OBD Code

U3963 Mercedes C 240 Error Code Repair Process :

Common Causes of Mercedes C 240 U3963 OBD2 Code

U3963 code for other Mercedes cars