Engine Coolant Temperature Sensor on Radiator, Checking
Diagnostic Procedures
Engine Coolant Temperature Sensor on Radiator, Checking
Special tools, testers and auxiliary items required
• Multimeter (VAG1526) or multimeter (VAG1715)
• Connector test kit (VAG1594)
• Wiring diagram
Test requirements
Fuses in E-box (in plenum chamber, left) must be OK:
Ground (GND) connections between engine and chassis must be OK.
Ignition switched off.
Test sequence
- Disconnect 2-pin connector from Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83) (arrow).
Checking resistance
- Measure resistance at Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83).
Range A displays resistance values for the temperature range of 0 to 50° C, range B displays resistance values for the temperature range of 50 to 100° C.
Read-out examples:
• 30° C is in range A and corresponds to a resistance of 1.5 to 2.0 kohms
• 80° C is in range B and corresponds to a resistance of 275 to 375 ohms
If specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) Sensor (on Radiator) (G83).
CAUTION!
• The 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.
- Generate readiness code.
If specified value is obtained:
- Check wires according to wiring diagram.
Checking wiring
- Connect test box to control module wiring harness , connect test box for wiring test.
- Check wires between test box and 2-pin connector for open circuit according to wiring diagram.
Terminal 1+socket 17
Terminal 2+socket 50
Wire resistance: max. 1.5 ohms
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: infinite ohms
- Erase DTC memory of Engine Control Module (ECM) , Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code.
If no malfunctions are detected in the wires and the resistance values are OK:
- Replace Motronic Engine Control Module (ECM) (J220).