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U2540 BMW Fault Code

Check U2540 OBD Fault Code Reason
Description:

Engine Coolant Temperature (ECT) Circuit High Input Indicates the sensor signal is greater than Self-Test maximum. The ECT sensor maximum is 4.6 volts or -50 C (-58 F). Note on some vehicles that are not equipped with an ECT sensor, CHT can be used and can set this DTC. Open circuit in harness Sensor signal short to power Damaged PCM Improper harness connection Damaged sensor ECT V PID reading greater than 4.6 volts with key ON and engine OFF or during any engine operating mode indicates a hard fault.

U2540 Code Symptoms :

See U2540 in engine

There are currently two main types of cylinder deactivation used today, depending on the type of engine. U2540 code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.

Diagnosis And Repairing U2540

U2540 OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.

How to fix U2540 code ?

See U2540 repair manual
  • Camshaft advance mechanism binding (VCT unit)
  • Damaged camshaft position (CMP) sensor
  • Fuel injectors harness is open or shorted
  • Faulty TCM or TCM programming

BMW Cars that meet U2540 error