Engine Coolant Temperature Sensor On Radiator, Checking
Special tools and workshop equipment 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: Refer to SYSTEM WIRING DIAGRAM
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 kΩ
- 80° C is in range B and corresponds to a resistance of 275 to 375 Ω
If specified value is not obtained:
-- Replace Engine Coolant Temperature (ECT) Sensor (on Radiator) -G83-.
- 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 Ω
-- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: ∞ Ω
-- 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- ENGINE CONTROL MODULE, REPLACING .