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Home >> Volkswagen >> 2004 >> New Beetle Convertible (1Y1) L4-1.8L Turbo (AWV) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Sensors and Switches - Computers and Control Systems >> Coolant Temperature Sensor/Switch (For Computer) >> Testing and Inspection >> With Generic Scan Tool

With Generic Scan Tool



Engine Coolant Temperature (ECT) Sensor, Checking

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements







- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- Engine must be cold.

Function test
- Connect diagnostic tester.
- Switch ignition on.
- Under address word 33, select "Diagnostic mode 1: Checking measured values."
- Select the measuring value "PID 05: Coolant temperature".
- Check specified value of coolant temperature:







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


Indicated1) Cause
approx. -40 degrees C Open circuit or short circuit to B+
approx. 143 degrees C Short circuit to Ground (GND)
1) If a temperature is indicated which differs greatly from ambient temperature of sensor, check sensor wires for contact resistance.


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

NOTE:
- The temperature increases in increments of 1.0 degrees 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.

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

Vehicles with engine code APH







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







- Bridge terminals 1 + 3 of connector using the respective adapter cables and observe the indication on display.

Vehicles with engine code AWP, AWV







- 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 the respective adapter cables and observe the indication on display.

Continuation for all vehicles

If indication jumps to approx. 143 degrees C:
- End diagnosis and switch ignition off.
- Replace Engine Coolant Temperature (ECT) Sensor -G62- with Engine Coolant Temperature (ECT) Sensor -G2-:

- Vehicles with engine code APH, item 13.
- Vehicles with engine code AWP, AWV, item 13 .

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If indication remains at approx. -40 degrees C:
- End diagnosis and switch ignition off.
- Check wires according to wiring diagram.

Continuation of test if indication is approx. 143 degrees C:
Vehicles with engine code APH







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

Vehicles with engine code AWP, AWV







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

Continuation for all vehicles
If indication jumps to approx. -40 degrees C:
- End diagnosis and switch ignition off.
- Replace Engine Coolant Temperature (ECT) Sensor -G62- with Engine Coolant Temperature (ECT) Sensor -G2-:
- Vehicles with engine code AWD, item 13 .
- Vehicles with engine code AWP, AWV, item 13.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If indication remains at approx. 143 degrees C:
- End diagnosis and switch ignition off.
- Check wires according to wiring diagram.

Checking wiring
- Connect test box to control module wiring harness, connect test box for wiring test.

Vehicles with engine code APH







- Check wires between test box and 4-pin connector for open circuit according to wiring diagram.
Terminal 1 + socket 108
Terminal 3 + socket 93
Wire resistance: max. 1.5 ohms
- Use wiring diagram to check wire between test box and 3-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)
Specified value: Infinite Ohms

Vehicles with engine code AWP, AWV







- Check wires between test box and 4-pin connector for open circuit 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)
Specified value: Infinite Ohms

Continuation for all vehicles
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohms

If no malfunctions are found in wire:

Vehicles with engine code APH







- Perform a resistance measurement at Engine Coolant Temperature (ECT) Sensor -G62- terminal 1 (signal) and 3 (Ground -GND-).

Vehicles with engine code AWP, AWV







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

Continuation for all vehicles







Range A displays resistance values for the temperature range of 0...50 degrees C, range B displays resistance values for the temperature range of
50...100 degrees C.

Read-out 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 specified value is not obtained:
- Replace Engine Coolant Temperature (ECT) Sensor -G62- with Engine Coolant Temperature (ECT) Sensor -G2-:
- Vehicles with engine code AWD, item 13.
- Vehicles with engine code AWP, AWV, item 13.

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are detected in the wires and the resistance values are OK:
- Replace Motronic Engine Control Module (ECM) -J220-.
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