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With Manufacturer's Scan Tool




Engine Coolant Temperature (ECT) Sensor -G62-, Checking

NOTE: The Motronic Engine Control Module (ECM) -J220- will use a replacement temperature value for an engine start as soon as there is a DTC stored in the DTC memory which affects the Engine Coolant Temperature (ECT) sensor -G62-. The temperature then rises according to a model stored in the ECM. When the engine has reached normal working temperature a fixed replacement value will be displayed after a certain period. This fixed value is also dependent on intake air temperature.


Special tools, test equipment and auxiliary items
- VAG 1551 scan tool or VAG 1552 mobile scan tool with VAG 1551/3B cable
- VAG 1598/31 test box
- VAG 1526 hand multimeter or VAG 1715 multimeter
- VAG 1594 adapter set
- Electrical Wiring Diagram

Test conditions
- Engine must be cold

Test sequence


NOTE: Only gold-plated terminals must be used to repair the terminals 3 and 4 in the connector for the Engine Coolant Temperature (ECT) sensor.


- Connect VAG 1551 scan tool ((VAG 1552). Switch ignition on and select Motronic Engine Control Module with "Address word" 01. Connecting scan tool and selecting Motronic Engine Control Module (ECM) -J220-. [1][2][3]Connecting VAG 1551 Scan Tool

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- for 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- for "Display group number 4" and confirm entry with -Q- button.

Indicated on display (1 to 4 = Display zones)


Read measuring value block 4 ->
1 2 3 4


- Read Engine Coolant Temperature (ECT) value in display zone 3.

Specification: approx. Engine Coolant Temperature (ECT)







If the specification is not obtained:
- Perform check according to following table:

Evaluating display group 4, display zone 3 - Engine Coolant Temperature (ECT)







If the specification is obtained:
- Start engine and run at idling speed.
Temperature value must increase uniformly


NOTE:
- Temperature increases in steps of 1.0 °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 sensor must be replaced.


- Press -> button.
- Press buttons -0- and -6- for "End output" function and confirm input with -Q- button.

Continuation of check when display approx. -48 °C:







- Disconnect 4-pin connector from Engine Coolant Temperature (ECT) sensor -G62- with Engine Coolant Temperature (ECT) sensor -G2- -arrow-.







- Bridge connector terminals 3 + 4 using auxiliary cables from VAG 1594 and observe display.

If display jumps to approx. 143.0 °C:
- Press -> button.
- Press buttons -0- and -6- for "End output" function and confirm input with -Q- button.
- Switch off ignition.
- Replace Engine Coolant Temperature (ECT) sensor -G62- with Engine Coolant Temperature (ECT) sensor -G2-, item 28.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery 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. -48.0 °C:
- Press -> button.
- Press buttons -0- and -6- for "End output" function and confirm input with -Q- button.
- Switch off ignition.
- Check wiring using Electrical Wiring Diagram.

Continuation of check when display approx. 143.0 °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. -48.0 °C:
- Press -> button.
- Press buttons -0- and -6- for "End output" function and confirm input with -Q- button.
- Switch off ignition.
- Replace Engine Coolant Temperature (ECT) sensor -G62- with Engine Coolant Temperature (ECT) sensor -G2-, item 28.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery 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. 143.0 °C:
- Press -> button.
- Press buttons -0- and -6- for "End output" function and confirm input with -Q- button.
- Switch off ignition.
- Check wiring using Electrical Wiring Diagram.

Checking wiring
- Remove inner plenum chamber cover, left.







- Connect VAG 1598/31 test box to control module wiring harness. Motronic Engine Control Module (ECM) -J220- is not connected by this action.







- Disconnect 4-pin connector from Engine Coolant Temperature (ECT) sensor -G62- with Engine Coolant Temperature (ECT) sensor -G2- -arrow-.







- Check wire for open circuit between test box and 4-pin connector using Electrical Wiring Diagram.
- terminal 3 + Socket 93
- terminal 4 + Socket 108

Wire resistance: max. 1.5 Ohms

- Check wiring between test box and 4-pin connector terminal 3 for short circuit to wire terminal 4 and to vehicle Ground (GND) using Electrical Wiring Diagram.
- terminal 3 + socket 108
- terminal 3 + vehicle Ground (GND)

Specification: Infinity Ohms

- Additionally check both wires for short to battery positive.

Specification: Infinity Ohms


If no wiring malfunctions are detected:







- Perform resistance measurement on Engine Coolant Temperature (ECT) sensor -G62- terminal C (signal) and D (Ground).







- Scale A shows resistance values for temperature range 0 to 50 °C and scale B the values for temperature range 50 to 100 °C.

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 the specification is not obtained:
- Replace Engine Coolant Temperature (ECT) sensor -G62- with Engine Coolant Temperature (ECT) sensor -G2-, item 28.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery 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 malfunction in the wiring and the resistance measurement values are OK:
- Replace Motronic Engine Control Module (ECM) -J220-.
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