Test Point 21

Fault, DTC 56 Test Point 21

Instrument cluster
Activation
No signal change

Possible causes, elimination, notes

Fault effect:
Reduced driving program.

NOTE: The Tiptronic control module (pin 25) is connected to the instrument cluster (pin II/17) via a serial data lead.

Specification:
Signal type = PWM
Frequency = 50 Hz
Level = 0... 12 V

Signal coding:







NOTE: There is no fault if the pulse width is 70 % with the engine running and with the selector lever in position "P".







1. Check the PWM signal with an oscilloscope.
2. Check wire from Tiptronic control module connector pin 25 to the instrument cluster connector II (white) pin 17 for open circuit, short to ground and short to B+.