With Generic Scan Tool

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

Recommended special tools and equipment







- VAG1526A multimeter
- VAG1594A connector test kit
- VAG1598/31 test box

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

Checking function
- Connect diagnostic tester. Diagnostic Tester, Connecting
- Switch ignition on.
- In diagnostic function "33 - OBD", select "Mode 1: Checking measuring 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 degree 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.

If indications do not resemble description:

Checking internal resistance







- Disconnect harness connector -2- at Engine Coolant Temperature (ECT) Sensor -G2-/-G62-.







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

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







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

If specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) Sensor -G62- -item 20-.

If specified value is obtained:

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







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

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

- Specified value: Wire resistance max 1.5 Ohm

- Also check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value:infinity Ohm (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". Diagnostic Mode 3: Check DTC Memory
2 - If necessary, erase DTC memory, "Mode 4: Reset/erase diagnostic data". Diagnostic Mode 4: Check Reset/Erase Diagnostic Data
3 - Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.