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Home >> Volkswagen >> 2001 >> Golf GL (1J1) L4-2.0L (AVH) >> Repair and Diagnosis >> Powertrain Management >> Sensors and Switches - Powertrain Management >> Sensors and Switches - Computers and Control Systems >> Coolant Temperature Sensor/Switch (For Computer) >> Testing and Inspection >> With Manufacturer's Scan Tool

With Manufacturer's Scan Tool



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

NOTE: If a DTC relating to the Engine Coolant Temperature (ECT) sensor -G62- is stored in DTC memory, the Engine Control Module (ECM) uses a replacement value when starting the engine (starting temperature replacement value). After this, the temperature rises according to a mapping specification stored in the Engine Control Module (ECM). For a warm engine, a fixed replacement value is indicated after a certain period of time. This fixed replacement value is also dependent on the intake air temperature.

Special tools and equipment
- V.A.G1551 scan tool (or VAG1552 mobile scan tool) with VAG1551/3 cable
- VAG1598/31 test box
- Multimeter Fluke 83 or equivalent
- VAG1594 connector test kit
- Wiring diagram

Test requirement
- Engine must be cold.

Test sequence
- Connect V.A.G 1551 scan tool (VAG1552). Then switch ignition on and select the Engine Control Module (ECM) using address word 01 [1][2]Reading and Clearing Diagnostic Trouble Codes

Indicated on display:

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Q- button to confirm input.

Indicated on display:

Read measuring value block
Enter display group number XXX

- Press 0, 0 and 4 for the function "display group number 4", and then press Q to exit from input mode.

Indicated on display: (1 to 4 = display fields)

Read measuring value block 4 ->
1 2 3 4

- Read coolant temperature value in display field 3.
Specification: approx. coolant temperature

If specified value is not obtained:
- Continue test according to the following table:






If specified value is obtained:
- Start engine and let run at idle.
The temperature should climb uniformly

NOTE:
The temperature climbs in increments of 1.0°C.
If the engine shows problems in certain temperature ranges and if the temperature does not climb uniformly, the temperature signal is intermittent and the sensor should be replaced.
When servicing terminals in the harness connector for the coolant temperature sensor, use only gold-plated terminals.

- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06. Press -Q- button to confirm input.

Continuation of test if indication is approx. -40°C:






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






- Bridge terminals 3 + 4 of connector using adapter cables from VAG1594 connector test kit, and observe what is indicated on display.

If indication jumps to approx. 140°C:
- Press -> button.
- Press buttons -0- and -6- to select "End data transfer" function 06. Press -Q- button to confirm input.
- Switch ignition off.
- Replace Engine Coolant Temperature (ECT) sensor (G62).
- Check DTC memory, repair any malfunctions and then erase DTC memory.

If indication remains approx. -40°C:
- Press -> button.
- Press buttons -0- and -6- to select "End data transfer" function 06. Press -Q- button to confirm input.
- Switch ignition off.
- Check wires according to wiring diagram.

Continuation of test if indication is approx. 140°C:






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

If indication jumps to approx. -40°C:
- Press -> button.
- Press buttons -0- and -6- to select "End data transfer" function 06. Press -Q- button to confirm input.
- Switch ignition off.
- Replace Engine Coolant Temperature (ECT) sensor (G62).
- Check DTC memory, repair any malfunctions and then erase DTC memory.

If indication remains at approx. 140°C:
- Press -> button.
- Press buttons -0- and -6- to select "End data transfer" function 06. Press -Q- button to confirm input.
- Switch ignition off.
- Check wires according to wiring diagram.

Checking wiring
- Remove wiper arms and wind cowl






- Connect VAG1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.






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






- Check wires between test box and 4- pin connector for open circuits according to wiring diagram.
Terminal 3 + socket 93
Terminal 4 + socket 108
Wire resistance: max: 1.5 Ohms

- Use wiring diagram to check wire between test box and 4-pin connector terminal 3 for short circuit to wire of terminal 4 and to vehicle Ground (GND).
Terminal 3 + socket 108
Terminal 3 + vehicle Ground (GND)
Specification: Infinity Ohms

- Also check both wires for shorts to battery B+.

If wiring is OK:






- Measure resistance at Engine Coolant Temperature (ECT) sensor -G62-, terminals C (signal) and D (Ground -GND-).






- Range A shows resistance values for temperature range from 0 - 50°C, and range B shows values for temperature range from 50 - 100°C.
Read-out examples:
30°C is in range A and corresponds to a resistance of 1.5 to 2.0k Ohms
80°C is in range B and corresponds to a resistance of 275 to 75 Ohms

If specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) sensor -G62-.
- Check DTC memory, repair any malfunctions and then erase DTC memory.

If wiring is OK and the resistance values are OK:
- Replace Engine Control Module (ECM).

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