Engine Coolant Temperature (ECT) Sensor -G62-, Checking

Engine Coolant Temperature (ECT) Sensor -G62- Checking

Special tools and equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAG5051 with VAG5051/1
- or
- VAG1551 with VAG1551/3A

Test requirement:
- Engine cold

Test sequence
- Connect VAS5051 tester or VAG1551 scan tool and select control module for engine electronics using "address word" 01. Engine must run at idle. [1][2]Scan Tool Connecting and Initial Checks

When indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read Measuring Value Block" and press -Q- button to confirm input.

When indicated on display


Read measuring value block Q
Enter display group number XXX

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

Indicated on display


Read Measuring Value Block 4
1 2 3 4


- Check indication in display field 3.

Display Group 004:

If display field 3 does not have a realistic indication:

- Disconnect connector at coolant temperature sensor.

Coolant temperature sensor with square connector:







- Connect multimeter between terminal 1 and 3 of sensor for resistance measurement.

Coolant temperature sensor with oval connector:







- Connect multimeter between terminal C and D of sensor for resistance measurement.

All models:
Range A shows the resistance values for the temperature range from 0-50 °C, and range B shows the values for the temperature range from 50-100 °C.







Read-out examples:
- 30 °C corresponds to a resistance of 1500 to 2000 Ohms
- 80 °C corresponds to a resistance of 275 to 375 Ohms

If specified value is not obtained:
- Replace coolant temperature sensor.

If specified value is obtained:
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM), do not connect ECM [1][2]Scan Tool Connecting and Initial Checks

Coolant temperature sensor with square connector:







- Check following wire connections for open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box
Terminal Socket
1 (signal) 93
3 108

Coolant temperature sensor with oval connector:







- Check following wire connections for open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box
Terminal Socket
3 108
4 (signal) 93

All models:
- Check both wires to each other for short circuit.
- Repair open circuit or short circuit if necessary.

If no malfunctions are found in wires:
- Replace Engine Control Module (ECM).