Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Coolant Temperature (ECT) sensor -G62-, checking
Special tools and equipment
- VAG1526 A
- VAG1594 A
- VAG1598/31
- VAS5051 with VAS5051/1
Installation location. Refer to Component locations, overview
Test requirements:
- Engine cold
Test sequence
- Connect testing and information system VAS5051. Refer to Vehicle diagnostic, testing and information system VAS5051, connecting and select functions and select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.
Display on VAS5051:
- Under -1- select diagnostic function "08 - Read measured value block".
Display on VAS5051:
1 - Enter display group
- Enter "004" for "display group number 004" in zone -2- and confirm entry by pressing -Q- button.
Display on VAS5051:
- Check indication in display field -3-.
| Display zones | ||||
| 1 | 2 | 3 | 4 | |
| Display group 004: Coolant temperature with engine idling | ||||
| Display | xxxx RPM | xx.x V | xxx.x°C | xxx.x°C |
| Display | Engine speed | Battery voltage | Coolant temperature | Intake air temperature |
| Range | -48.0 to 143.0°C | |||
| Specif. value | xxxx RPM | 12.0 to 15.0 V | The temperature reading should increase evenly | from ambient temperature up to 110°C |
If display zone 3 shows an implausible value:
- Disconnect connector -2- at Engine Coolant Temperature (ECT) sensor -G2-/-G62-.
- Connect multimeter between terminals C and D of sensor to measure resistance.
Range A shows resistance values for temperature range 0 to 50°C and range B shows the values for temperature range 50 to 100°C.
Sample readings:
- 30°C corresponds to a resistance of 1500 to 2000 Ω
- 80°C corresponds to a resistance of 275 to 375 Ω
If specified value is not attained:
- Replace engine coolant temperature sensor.
If specified value is attained:
- Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. Refer to Wiring and component check with test box VAG 1598/31 .
- Check for open circuit and short to positive or ground in following wiring connections:
| Connector Terminal |
Test box VAG1598/31 Socket |
| 3 | 108 |
| 4 (signal) | 93 |
- Test for short circuits between two wires.
- Repair any open/short circuit as necessary.
If no wiring malfunction is detected:
- Replace engine control module. Refer to Engine Control Module (ECM) (without metal anti-theft housing), replacing .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.