Checking wiring

Connect test box to control module wiring harness. Refer to Test box, connecting for wiring test .

Vehicles with 80-pin control module

Fig 1: Identifying Harness Connector Terminals 1 & 3

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Check wires between test box and 4-pin connector for open circuit according to wiring diagram.

Terminal 1 + socket 70

Terminal 3 + socket 54

Wire resistance: max. 1.5 Ω

Vehicles with 121-pin control module

Fig 2: 4-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Check wires between test box and 4-pin connector for open circuit according to wiring diagram.

Terminal 3 + socket 112

Terminal 4 + socket 104

Wire resistance: max. 1.5 Ω

Vehicles with 154-pin control module

Connect adapter cable (V.A.G 1598/39-1) to test box (V.A.G 1598/42).

Fig 3: 4-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Check wires between test box and 4-pin connector for open circuit according to wiring diagram.

Terminal 3 + socket 52

Terminal 4 + socket 53

Wire resistance: max. 1.5 Ω

Continue for all vehicles

Check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: ∞ Ω

If no malfunctions are found in wires:

Vehicles with 80-pin control module

Fig 4: ECT Sensor

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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

Fig 5: Engine Coolant Temperature Sensor G62 Terminals 1 & 3

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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

Vehicles with 121-pin control module

Fig 6: ECT Sensor Terminals 1 & 3

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Disconnect connector at coolant temperature sensor.
Measure resistance between terminals 3 + 4 on sensor.

Vehicles with 154-pin control module

Fig 7: Engine Coolant Temperature Sensor Connector

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Disconnect connector at coolant temperature sensor.

Fig 8: 4-Pin Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Measure resistance between terminals 3 + 4 on sensor.

Continue for all vehicles

Fig 9: Resistance Values Graph

Courtesy of VOLKSWAGEN UNITED STATES, INC.

See diagram for specified value

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

Read-out examples:

30 ° C corresponds to a resistance of 1500 to 2000 Ω
80 ° C corresponds to a resistance of 275 to 375 Ω

If specified value is not obtained:

Replace Engine Coolant Temperature (ECT) Sensor -G62- with Engine Coolant Temperature (ECT) Sensor -G2-:

Vehicles with engine code ALH, Overview of component locations. Refer to item 10 in Component Locations, overview (vehicles with engine code ALH)
Vehicles with engine code BEW, Overview of component locations. Refer to item 8 in Component Locations, overview (vehicles with engine code BEW) .

Erase DTC memory of control module for Diesel-Direct fuel injection system. Refer to Diagnostic mode 4: Reset/erase diagnostic data .
Generate readiness code.

If no malfunctions are detected in the wires and the resistance values are OK:

Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to Control module for Diesel-Direct Fuel Injection System, replacing .
Generate readiness code.