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". [1][2]Scan Tool Connecting and Initial Checks
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. [1][2]Scan Tool Connecting and Initial Checks
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).