Engine Coolant Temperature (ECT) Sensor - G62 -, Checking
Engine Coolant Temperature (ECT) Sensor -G62, Checking
Test conditions
- Engine cold
- Connect vehicle diagnostic, testing and information system VAS 5051 or VAG1551 scan tool to vehicle and select engine electronics control module by entering address word "01". Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks", Testing and Inspection
When doing this the engine must be at idle.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select function "Read Measuring Value Block" and confirm entry with -Q- button.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons -0-, -0- and -4- to select Display Group 4 and confirm entry with -Q- button.
Indicated on display
Read Measuring Value Block 4 ->
1 2 3 4
- Check readout for coolant temperature sender in display field 3.
Display Group 004:
If display field 3 does not display a realistic value:
- Disconnect harness connector from coolant temperature sensor.
Coolant temperature sensor with square connector:
- Connect multi-meter (resistance measurement) between terminals 1 and 3 of sensor.
Coolant temperature sensor with oval connector:
- Connect multi-meter (resistance measurement) between terminals 3 and 4 of sensor.
All:
Scale A shows resistance values for temperature range 0 - 50 °C and scale B the values for temperature range 50-100 °C.
Examples:
- 30 °C corresponds to a resistance from 1500...2000 Ohms
- 80 °C corresponds to a resistance from 275...375 Ohms
If value does not match the specification:
- Replace coolant temperature sensor.
If the value does match the specification:
- Connect test box VAG1598/31 to wiring harness for engine control module. Do not connect to the engine control module itself. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks", Testing and Inspection
Coolant temperature sensor with square connector:
- Check following wiring connections for open circuits and short circuits to B+ or Ground (GND)
Harness VAG1598/31 test
connector Terminal box Socket
1(Signal) 93
3 108
Coolant temperature sensor with oval connector:
- Check following wiring connections for open circuits and short circuits to B+ or Ground (GND)
Harness VAG1598/31 test box Socket
connector Terminal
3 108
4 (Signal) 93
All:
- Check wiring for short circuit to each other.
- If necessary eliminate open circuit or short circuit.
If no malfunction is identified in the wiring:
- Replace Engine Control Module (ECM).