Description

Implausible frequency

Effects on the driving operation

No retarder operation

Driving in reverse gear not possible or limited.

No ANS-function

Driving in 1st gear only. Higher gears at very high engine speed only (engine protection).

If a substitute function is available, the fault may only cause poor gearshifts and hard retarder activation.

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

Possible causes

Implausible speed ratios between engine output speed and transmission output speed have been measured in the mechanical gear which are not possible due to the transmission ratio. Attention: The engine sensor can also be the cause of this fault!

Possible causes: The sensors are installed in the wrong position, defect of the speed sensors, no correct adhesion of the disks.

Installation point of the speed sensor

Place of action

Transmission mechanics

Transmission output speed sensor

Engine speed sensor

Turbine speed sensor

Instruction

Check all frequency transmitters for correct signal generation and correct installation (distance to the measurement gear).

Setting conditions of the event

No description available.

Test conditions of the event

No description available.

Troubleshooting

• Replace the sensor with a new one and make a test drive to check if the fault has been eliminated.
• Check the installation of the speed sensor.
• Check the size of the air gap between sensor and measuring gear.

The distance can be measured as follows:

• Dismantle the sensor.
• Make sure that a tooth of the measuring gear comes to a halt in the center of the sensor axis.
• Measure the distance from the assembly surface to the tooth using a depth gauge.
• Subtract the sensor length from the measured value (assembly surface to sensor tip).

If the fault could not be removed, the measuring gear is possibly defective. After having contacted the Voith customer service, replace the measuring gear with a new one.

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 the function.

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

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

These steps are necessary to ensure the entire vehicle functions.

See also:

		Aftersales service index