Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

Engine Coolant Temperature (ECT) sensor -G62, checking

- Connect Vehicle Diagnostic, Testing and Information System VAS5051 or VAG 1551 Scan Tool to vehicle and select engine electronics control module by entering address word "01", Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/ VAS 5051 Scan Tool" Testing and Inspection . When doing this the engine must be at idle.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.

Indicated on display

Read Measuring Value Block
Input display group number XXX

- Press buttons -0-, -0- and -4- to select "display group number 004" and confirm entry with -Q- button.

Indicated on display


Read Measuring Value Block 4 ->
1 2 3 4


- Check readout for coolant temperature sender in display field 3.







Testing wiring
- Switch ignition off.
- Disconnect harness connector from sensor.
- Connect VAG 1598/31 test box to wiring harness for engine control module. DO NOT connect to engine control module itself, Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/Connecting VAG 1598/31 Test Box" Testing and Inspection







- Check wiring from 4-pin connector to engine control module for open circuit or short circuit to B+ or Ground (GND).

4-pin connector on VAG 1598/31 test
wiring harness, socket box socket
3 108
4 93

Resistance in wiring: max. 1.5 Ohms

- Correct any open/short circuit as necessary.

If no wiring malfunction is detected:
- Replace Engine Coolant Temperature (ECT) Sensor -G62.
- Display readiness code, Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Displaying Readiness Code" Testing and Inspection . Readiness code must be generated if DTC memory was erased, Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code" Testing and Inspection