Test Point 15

Fault, DTC 91 Test Point 15

Stall speed, transmission input
Signal implausible

Possible causes, elimination, notes

Fault effect:
Reduced driving program.

NOTE: The ratio of transmission input speed/engine speed is monitored.

1. Check sensor for the transmission input speed on Tiptronic control module connector pins 16 and 44 with an ohmmeter.

Nominal value: 230... 300 Ohms.

2. Check wiring from control module pin 16 (or 44) to the 16-pole transmission connector pin 5 (or 6) for open circuit, short to ground and short to B+.
3. Check shield on control module connector pin 23.
4. Check sensor on transmission socket pins 5 and 6 with an ohmmeter.

Nominal value: 230... 300 Ohms.

NOTE: The hydraulic control unit must be removed before the sensor can be tested.

5. If items 1... 4 are OK and no other faults are stored, there is a mechanical/hydraulic fault in the transmission (e.g. ATF level not OK, defective converter, slipping clutches or brakes).