P1770

P1770
Load signal from ECm

Function:
The ECm signals a fault directly to the Tiptronic control module via a data lead (CAN bus).

Diagnosis Condition:
- Vehicle driving (see ECm test plan P1140)




Wiring Diagram:




Diagnosis Procedure:



1 Check data leads from Tiptronic control module to ECm for continuity.
1. Pull off Tiptronic control module connector.
2. Pull off ECm connector.
3. Connect ohmmeter to Tiptronic control module connector pin 85 (or pin 86) and ECm connector pin 85 (or pin 86).

Display: 0 ... 5 ohm.

If infinite ohm is displayed, check wiring harness for chafing and pinching damage.

1 Check data leads from Tiptronic control module to ECm for short circuit to ground.
1. Connect ohmmeter to Tiptronic control module connector pin 85 (or pin 86) and ground.

Display: infinite ohm.

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

1 Check data leads from Tiptronic control module to ECm for short circuit to B+.
1. Switch on ignition.
2. Connect voltmeter to Tiptronic control module connector pin 85 (or pin 86) and ground.

Display: 0 Volt.

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