MIL ON - Poor Idle/Stalls, Loss of Power, Exhaust Smoke
Group: 24Number: 93-04
Date: November 15, 1993
Subject:
Engine Coolant Temperature (ECT) Sensor, replacing
Model(s):
All models with ECT Sensor all m.y.
Condition
A driveability problem can lead to the replacement of the Engine Coolant Temperature (ECT) Sensor when it in unnecessary to do so.
The following observations can lead to a suspected faulty ECT Sensor:
^ VAG 1551 Scan Tool indicates ECT Sensor is faulty
^ Malfunction Indicator Light is on
^ Vehicle loses power
^ Excessive visible exhaust smoke
^ Stalling and poor idle
Suspected ECT Sensor problems can be caused by:
^ Incorrect, disconnected or faulty wiring
^ Corroded terminals
^ Faulty input to Engine Control Module (ECM)
Service
Follow these steps to avoid unnecessary repairs when diagnosing suspected ECT Sensor problems:
- Determine if problem is ECT Sensor related
- Check for correct connections at the ECT Sensor
- Check ECT Sensor wiring for damage
- Check that Ground connections are clean and make good contact
- Check ECT Sensor terminals (tin-plated) and clean with VW contact cleaner, Part No. G 000 700 04, or equivalent
- Check that terminals are properly installed in wiring connectors. Use appropriate wiring diagram
- Use VAG 1598 and digital multimeter Fluke 83 (US 1119) to check resistance of ECT Sensor circuit when engine is cold and again when engine is hot.
- Road test vehicle to check performance.
- Check DTC Memory
- Replace ECT Sensor if necessary
- Road test vehicle
- If no improvement, replace ECM
- Road test vehicle
Use the following Part Identifier Numbers:
CIS 2519
Digifant I 2462
Digifant II 2462
Motronic 2.9 2462