Description

Sensor voltage too low

If the sensor voltage drops below 4.5 V, the speed sensor signal cannot be evaluated anymore.

Effects on the driving operation

Hard shifts.

No switching into reverse gear.

Main pressure to maximum.

Reduction of the engine torque to protect the transmission.

If the engine transmission output speed sensor is simultaneously defective, only limp-home mode available.

The engine speed and/or the values derived on its basis are incorrectly set in the CAN communication.

Possible causes

Defect of the sensor, low-resistance connection between the two sensor terminals or defect of the transmission control unit

Place of action

Engine speed sensor (sensor voltage)

Instruction

Measure voltage at the speed sensor.

Check plug connections, cabling and sensor.

Setting conditions of the event

No description available.

Testing conditions of the event

No description available.

Final function check

If the defective component cannot be clearly identified, you should try to reproduce the fault:

• Reinstall the component in the vehicle.
• Test function.

After the fault has been eliminated, the following steps have to be carried out:

• Conduct a test drive with function check.
• Read the fault memory
• Check transmission for leaks.
• Perform a final visual inspection.

These steps are necessary to ensure the entire vehicle functions correctly.