With Manufacturer's Scan Tool
Engine Coolant Temperature (ECT) Sensor -G62-, Checking
Special tools and equipment
- V.A.G1551 scan tool or V.A.G1552 mobile scan tool with V.A.G1551/3B cable
- V.A.G1598/31 test box
- V.A.G1526 or Fluke 83 multimeter.
- V.A.G1594 adapter set
- Wiring diagram
Test conditions
- Engine must be cold.
Test sequence
- Connect V.A.G1551 scan tool (V.A.G1552). Switch ignition on and select engine control module with the "Address word" 01.(Connecting scan tool and selecting engine control module. [1][2][3]Connecting VAG 1551 Scan Tool)
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
Indicated on display:
Read measured value block HELP
Input display group number XX
- Press keys 0, 0 and 4 for "Display group number 4" and confirm entry with Q key.
Indicated on display: (1 to 4 = Display zones)
Read measured value block 4
1 2 3 4
- Read off coolant temperature value in display zone 3.
Specification: approx. coolant temperature
If the specification is not obtained:
- Perform check according to following:
Display1) Cause
Approx. -48 degrees C Open circuit or short to positive
Approx. 143 degrees C Short to Ground (GND)
1)If a temperature is displayed which deviates greatly from the ambient temperature of the sender, check sender wiring for transfer resistances. Note when doing this that sender is heated from external sources, e.g. radiated heat when engine is not running.
If the specification is obtained:
- Start engine and run at idling speed.
The temperature value must increase uniformly
NOTE:
- Temperature increases in steps of 1.0 degrees C.
- If irregular engine running occurs in certain temperature ranges and the temperature figure does not increase without interruption, the temperature signal is temporarily interrupted and the sender must be replaced.
- Press -> key.
- Press keys 0 and 6 for function "End output" and confirm entry with Q key.
Continuation of check when display approx. -48 degrees C
- Disconnect 4-pin connector from engine coolant temperature (ECT) sensor -G62- with engine coolant temperature (ECT) sensor -G2- (arrow).
- Bridge connector contacts 3 + 4 using adapter cables from V.A.G1594 and observe display.
If display jumps to approx. 143 degrees C:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Replace engine coolant temperature (ECT) sensor -G62-.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory.
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
If display remains at approx. -48 degrees C:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Check wiring using wiring diagram.
Continuation of check when display approx. 143 degrees C:
- Disconnect 4-pin connector from engine coolant temperature (ECT) sensor -G62- with engine coolant temperature (ECT) sensor -G2- (arrow).
If display jumps to approx. -48 degrees C:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Replace engine coolant temperature (ECT) sensor -G62-.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory.
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
If display remains at approx. 143 degrees C:
- Press -> key.
- Press keys 0 and 6 for "End data transfer" function and confirm input with Q key.
- Switch ignition off.
- Check wiring using wiring diagram.
Checking wiring
- Connect V.A.G1598/31 test box to control module wiring harness. Engine control module remains disconnected.
- Disconnect 4-pin connector from engine coolant temperature (ECT) sensor -G62- with engine coolant temperature (ECT) sensor -G2- (arrow).
- Check wiring between test box and 4-pin connector for open circuit using wiring diagram.
Contact 3 + socket 93
Contact 4 + socket 108
Wire resistance: Max. 1.5 Ohms
- Check wiring between test box and 4-pin connector contact 3 for short circuit to wire contact 4 and to vehicle Ground (GND) using wiring diagram.
Contact 3 + socket 108
Contact 3 + vehicle Ground (GND)
Specification: Infinite Ohms
- Check both wires for short to battery positive.
If no malfunction in wire is detected:
- Perform resistance measurement on Engine Coolant Temperature (ECT) sensor -G62- contact C (signal) and D (Ground (GND)).
Scale A shows resistance values for temperature range 0 to 50 degrees Cand scale B the values for temperature range 50 to 100 degrees C.
Examples:
- 30 degrees C is in range A and corresponds to a resistance of 1.5 to 2.0 k Ohms
- 80 degrees C is in range B and corresponds to a resistance of 275 to 375 Ohms
If the specification is not obtained:
- Replace engine coolant temperature (ECT) sensor -G62-.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory.
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
If there is no fault in the wiring and the resistance measurement values are OK.
- Replace engine control module.