Engine Coolant Temperature (ECT) Sensor (On Radiator), Checking

Engine Coolant Temperature (ECT) Sensor (on Radiator), Checking

NOTE: Use only gold-plated terminals when servicing terminals in the harness connector.

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Test requirements
- Fuses on E-box in engine compartment, left side, must be OK.

NOTE: Fuses on this fuse holder are labelled "SB" in the wiring diagram.







- Fuses on fuse holder in instrument panel, left side, must be OK.

NOTE: Fuses on this fuse holder are labelled "SC" in the wiring diagram.

- Ground (GND) connections between engine and chassis must be OK.
- Ignition switched off.

Test sequence
Observe safety precautions.
Observe rules for cleanliness.

- Remove noise insulation







- Disconnect 2-pin connector -arrow- from Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83-.

Checking resistance







- Check resistance of Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- between terminals using adapter cables.







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 is in range A and corresponds to a resistance of 1.5 to 2.0 kohms
- 80 degrees C is in range B and corresponds to a resistance of 275 to 375 ohms

NOTE: Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83- has a negative temperature coefficient (NTC). This means: the higher the temperature the lower the resistance value.

If specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83-.

CAUTION:
- Cooling system is under pressure.
- Danger of scalding when opening.

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:
- Check wires to Engine Control Module (ECM) according to wiring diagram.

Checking wires to Engine Control Module (ECM)
- Connect test box to 94-pin connector of wiring harness, connecting test box for wiring test. Test Box, Connecting For Wiring Test

Engine Control Module (ECM) is not connected.







- Check wires between test box and 2-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Terminal 1 + socket 26
Terminal 2 + socket 12

Wire resistance: max. 3.0 ohms

- Also check wires for short circuit to each other.

Specified value: infinity ohms

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in the wires and the resistance value is OK:
- Replace Engine Control Module (ECM) -J623-.