Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

Engine Coolant Temperature (ECT) sensor -G62-, checking

Installation location of engine coolant temperature sensor.
- Connect Vehicle Diagnostic, Testing and Information System VAS 5051 or V.A.G 1551 Scan Tool and select engine electronics control module 1 with "Address word" 01. For this purpose, engine must be running at idle speed.

Indicated on display
Rapid data transfer HELP
Select function XX


- Press keys 0 and 8 for function "Read measured value block" and confirm entry with Q key.

Indicated on display


Read measured value block
Enter display group number XXX


- Press keys 0, 0 and 4 for "display group number 4" and confirm entry with Q key.

Indicated on display


Read measured value block 4 ->
1 2 3 4


- Check specified value for engine coolant temperature sensor in display zone 3

Display Group 4:

Checking wiring
- Switch ignition off.
- Unplug connector from sensor.
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Connecting VAG 1598/31 Test Box
- Check wiring from 4 pin connector ...
- ... to engine control module for checking for open circuit and short to positive or Ground.

4-pin connector
on wiring harness, socket Test box VAG 1598/31, socket

3 108
4 93

Wire resistance: max. 1.5 Ohm

- Correct any open/short circuit as necessary.

If no wiring malfunction is detected:
- Replace Engine Coolant Temperature (ECT) sensor -G62-.
- Read readiness code. If DTC memory was erased, re-generate readiness code.