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Safety computer
AD conversion defective

Description
Effects on the driving operation
Possible causes
Function of the safety computer
Place of action
Instruction
Setting conditions of the event
Test conditions of the event
Final function check
See also:
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Description

AD conversion defective

The 2.5-V test voltage for testing the analog multiplexer and the AD converter is above the allowed maximum value.

Effects on the driving operation

Driving operation is blocked for safety reasons. The transmission assumes a safe state.

Possible causes

Internal fault of the safety computer

Internal fault of the control unit

Function of the safety computer

The safety computer (S-CPU) monitors safety-relevant signals which the function computer (F-CPU) sends or receives. If the safety computer detects an inadmissible condition, it initiates a reset of the function computer. During that time, the transmission system is in a safe mode (neutral).

Driving operation is only released if both the function computer AND the safety computer give their approval simultaneously. After the release the safety switch in the transmission control unit is closed and the ground of the solenoid valves is connected to the battery ground. Only then can the solenoid valves be activated and enable driving operation.

monitored signal private CAN (gear selection)
S-CPUN1 / N2monitored speeds
ALIVEalive signal of F-CPU to S-CPUMVmonitored actuation of all solenoid valves
COMMcommunication between F-CPU and S-CPUMV-GNDground applied by safety switch
-BATTbattery ground


Place of action

No description available.

Instruction

Should the fault not disappear, please contact the VOITH customer service.

Setting conditions of the event

No description available.

Test 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 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


© by Voith Turbo GmbH & Co. KG, S. Brunnengräber
send remarks to stefan.brunnengraeber@voith.com (documentation department)