Engine Coolant Temperature Sensor -G62- 1 Checking (ECT)

Engine Coolant Temperature Sensor -G62- 1 Checking (ECT)

Special and Equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAS5051 with VAG5051/1
or
- VAG1551 with VAG1551/3B

Test requirement:
- Engine cold

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

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
Input 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 valve 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 :


NOTE: Intake air hose between Mass Air Flow (MAF) sensor and intake air elbow must be removed in order to be able to reach the coolant temperature sensor.


- Disconnect connector at coolant temperature sensor.

Coolant temperature sensor with square connector:







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

Coolant temperature sensor with oval connector:







- Connect multimeter between terminal 3 and 4 of connector 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 ECM, do not connect ECM. Connecting VAG 1598/31 Test Box

Coolant temperature sensor with square connector:







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







Coolant temperature sensor with oval connector:







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







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).