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

CHECKING ENGINE COOLANT TEMPERATURE SENSOR

Requirement
^ Engine cold.

Procedure
- Connect VAG 1551 Scan Tool (ST).
- Start engine and let idle.
- Select function 08 "Read measurement block".

^ Display will appear as shown:

Read measurement block 1
1 2 3 4

- Observe coolant temperature value in channel 1 of display.

NOTE:
- Temperature value must increase uniformly without interruption.

- If performance malfunctions occur during certain temperature ranges and the temperature value does not increase uniformly, the temperature signal is intermittent and the sensor should be replaced.

- Press --> button.
- Press 0 and 6 buttons to select function 06 "end data transfer".
- Press Q button to enter input.
- If the temperature value does NOT change:

- Perform electrical testing. Refer to Diagnostic Charts / Electrical Test Steps (ECM Pinout) / Test Steps 11 and/or 28. Testing and Inspection
- If necessary, relieve cooling system pressure and replace Engine Coolant Temperature (ECT) sensor (G62).