With Generic Scan Tool

Engine Coolant Temperature (ECT) sensor -G62-, checking







Recommended special tools and equipment
- V.A.G1526A hand multimeter
- V.A.G1594A connector test kit
- V.A.G1598/31 test box

Test requirements:
- Fuses for engine electronics OK
- Engine cold

Checking function
- Connect diagnostic tester. Connect Diagnostic Tester
- Switch ignition on.
- In diagnostic function "33 - OBD", select "Mode 1: Checking measured values."
- Select the desired measuring value "PID 05: Coolant temperature".

Specified value: approx. ambient temperature

NOTE: If a temperature is indicated which differs greatly from ambient temperature of sensor, check sensor and sensor wires for contact resistances and open circuit.

- Start engine and let run at idle.

Specified value: Temperature value must rise evenly

NOTE:
- The temperature increases in increments of 1.0 degrees C.
- If the engine shows problems in certain temperature ranges and if the temperature does not climb uniformly, the temperature signal is intermittent and the sensor should be replaced.

- End diagnosis and switch ignition off.

If indications do not resemble description:

Checking internal resistance







- Disconnect electrical harness connector at Engine Coolant Temperature (ECT) Sensor -G2-/-G62- (arrow).







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

Range A displays resistance values for the temperature range of 0 to 50 degrees C, range B displays resistance values for the temperature range of 50 to 100 degrees C.







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

If specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) Sensor -G62-.

If specified value is obtained:

Checking wire connections
- Connect test box to wiring harness of Engine Control Module (ECM). ECM is not connected. Test Box, Connecting For Wiring and Component Test







- Check the following wire connections for open circuit according to wiring diagram.

Harness connector Terminal Test box Socket
3 108
4 (signal) 93

Specified value: Wire resistance max 1.5 Ohms

- Check wires for short circuit to each other as well as to B+ and Ground (GND).

Specified value: infinite Ohms (no continuity)

- If necessary, repair wire connection.

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

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory. Mode 3: Check DTC Memory
2. If necessary, erase DTC memory. Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.