Coolant Temperature Sensor, Checking
Testing without VAG 1551Fig. 3 Temperature sensors I & II operating specifications:
- Check temperature and resistance of Engine Coolant Temperature (ECT) sensor.
- If resistance is not within specifications on graph replace ECT sensor.
Testing with VAG 1551
- Engine must be cold to observe sensor through out range
- Connect and start operation of VAG 1551 Refer to Connecting and Operating VAG 1551 Scan Tool
- Start engine and let idle
- select function 08 "Read test value block" Refer to VAG w/ VAG 1551- Test Value Block, Reading
- Select display group 01, display will appear as shown:
Read test value block 1
1 2 3 4
- Observe display value in field 2
- Engine temperature must be uniform and increase without interruption
- Select function O6 "Ending output"
- If displayed value does not increase
- Perform electrical checks, Refer to VAG 1598 Pin Out Box/ Electrical Checks,Test step 18
- If necessary, replace sensor
Note:If engine malfunctions occur during certain temperature ranges and the display value does not increase without interruption. Temperature signal has been interrupted and the ECT sensor must be replaced.