U3954 BMW Fault Code

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.

U3954 Code Symptoms :

When you turn on the ignition, the Service Engine Soon or Check Engine U3954 light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the U3954!

Diagnosis And Repairing U3954

U3954 OBD 2 code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.

How to fix U3954 code ?

• Camshaft advance mechanism binding (VCT unit)
• Faulty Mass Air Flow (MAF) sensor
• Damaged ECM
• Incorrect fuel pressure

Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code U3954, so consult the manual to locate the brake fluid reservoir.

Bear in mind that a low fluid level can set code U3954 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.