P1766

P1766
Throttle-valve signal <-ECM control unit

Function
The ECM control unit receives the throttle-valve signal from the throttle-valve potentiometer and forwards it to the transmission control unit. The throttle-valve signal is used for load-dependent calculation of the shifting times. If the signal is missing, the default throttle-valve value of 9% is used and kickdown shifting does not take place.

Diagnosis conditions
A fault is detected and stored with the engine at idle speed.





Wiring diagram





Diagnosis procedure

Check voltage signal at transmission control unit connector pin 7.
1. Pull off transmission control unit connector.
2. Switch on ignition.
3. Connect voltmeter to transmission control unit connector pin 7 and ground.
- Indication: approx. 1 Volt at idle speed and approx. 10 Volt at full throttle.

Check wire from transmission control unit to ECM control unit for continuity.
1. Pull off transmission control unit connector.
2. Pull off ECM control unit connector.
3. Connect ohmmeter to transmission control unit connector pin 7 and ECM control unit connector pin 82.
- Indication: 0...5 ohms
- If infinite resistance ohm is indicated, check wiring harness for crushing and chafing damage.

Check wire from transmission control unit to ECM control unit for short circuit to ground.
1. Connect ohmmeter to transmission control unit connector pin 7 and ground.
- Indication: infinite resistance
- If 0...5 ohms is indicated, check wiring harness for crushing and chafing damage.

Check wire from transmission control unit to ECM control unit for short circuit to plus.
1. Switch on ignition.
2. Connect voltmeter to transmission control unit connector pin 7 and ground.
- Indication: 0 Volt
- If battery voltage is indicated, check wiring harness for crushing and chafing damage.