U2940 Mercedes B Class OBD Code

OBD/2 U2940 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.

At this point we are assuming that the fuses and relays are good. You will need to locate the PCM/TCM and the power input signal circuit using your vehicle information source. Unplug the connector from the PCM/TCM, place the ignition switch in the ON position, and probe the appropriate circuit with the positive test lead of the DVOM.

U2940 Mercedes B Class Error Code Repair Process :

If your vehicle failed a U2940 test and the U2940 Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses transmission over temperature condition a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look transmission over temperature condition: Any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression. Use your OBD Express DIY to look at the oxygen sensor outputs, coolant temperature, airflow, calculated engine load, and inlet air temperature.

Common Causes of Mercedes B Class U2940 OBD2 Code

A common cause of code U2940 is the failure of Transmission Over Temperature Condition, but there are several other possible causes as well, such as ;

Exhaust tube
Erratic camshaft position due to low oil pressure
EVAP system hose leaking
Air fuel ratio (A/F) Sensor 1 Bank 1 circuit poor electrical connection

U2940 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

U2940 Mercedes B Class OBD Code

U2940 Mercedes B Class Error Code Repair Process :

Common Causes of Mercedes B Class U2940 OBD2 Code

U2940 code for other Mercedes cars