Instrument Cluster Triggering - No Signal Change

P1764

Instrument cluster triggering - no signal change

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

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

Diagnosis condition
- Ignition on

P1764:

Wiring diagram







Diagnosis procedure

NOTE: The pulse width can be checked with the Porsche System Tester 2 (Instrument cluster actual values/Tiptronic).







1 Check PWM signal with the Porsche System Tester 2.

1. Connect Porsche System Tester 2 and call up "Instrument cluster actual values/Tiptronic".

Move selector lever to position "P" and run engine at idle speed.
Display: 70 %

NOTE: The pulse width in the individual gears can also be tested using the Porsche System Tester 2 while the vehicle is being driven.

The following values must be achieved:







2 Check wire from Tiptronic control module to instrument cluster for continuity.

1. Pull off instrument cluster connector II (white). (The dashboard insert must be removed for this purpose)
2. Pull off Tiptronic control module connector.
3. Connect ohmmeter to Tiptronic control module connector pin 25 and instrument cluster connector II (white) pin 17.

Display: 0... 5 Ohms

If infinity Ohm is displayed, check wiring harness for chafing and pinching damage.

2 Check wire from Tiptronic control module to instrument cluster for short circuit to ground.

1. Connect ohmmeter to Tiptronic control module connector pin 25 and ground.

Display: infinity Ohm

If 0... 5 Ohm is displayed, check wiring harness for chafing and pinching damage.

2 Check wire from Tiptronic control module to instrument cluster for short circuit to B+.

1. Switch on ignition.
2. Connect voltmeter to Tiptronic control module connector pin 25 and ground.

Display: 0 Volt

If battery positive voltage is displayed, check wiring harness for chafing and pinching damage.