1. Connect the VAG 1551 tester and dial "01" to select the "Address word" function of the engine control unit. The engine should be idling. The display should show the following information:
2. Press "08" to select the "Read measured value block" function and confirm by pressing the "Q" button. The display should show the following information:
3. Press "002" to select the "Display Group 2" function and press "Q". The display should show the following information:
4. Read the incoming air temperature in field 4 of the display.
Continue testing at -33°C
5. Disconnect wiring connector 1 from sensor 2 (Fig. 3.37).
6. Shunt contacts 1 and 2 of the wiring connector using auxiliary wires from the VAG 1594 tester and observe the readings on the display.
The display shows approximately 118°C:
- press "→";
- press "06" to select the "Complete Output" function and confirm by pressing the "Q" button;
- turn off the ignition;
- replace the intake air temperature sensor 2.
The display shows approximately -33°C:
- press "→";
- press "06" to select the "Complete Output" function and confirm by pressing the "Q" button:
- turn off the ignition;
- connect the VAG 1598/18 tester to the engine control unit wiring harness;
- check the wire between the tester and the connector for an open circuit: socket 43 of the tester and contact 2 of the four-pin connector of the wires (fig. 3.34). Specified value: max. 1.5 Ohm.
- check the wires for short circuit to positive. Specified value: ∞ Ohms.
- check the wire between the tester and the connector for continuity: socket 17 of the tester and contact 1 of the four-pin wiring connector. Specified value: max. 1.5 ohms.
7. If no fault is found in the wires, then replace the engine control unit.
Continue testing at 118°C
8. Disconnect wiring connector 1 from sensor 2 (Fig. 3.37).
9. Shunt contacts 1 and 2 of the wiring connector using auxiliary wires from the VAG 1594 tester and observe the readings on the display.
The display shows approximately -33°C:
- press "→";
- press "06" to select the "Complete Output" function and confirm by pressing the "Q" button;
- turn off the ignition;
- replace the intake air temperature sensor 2.
(View the original article on the resource vwmanual)
The display shows approximately 118°C:
- press "→";
- press "06" to select the "Complete Output" function and confirm by pressing the "Q" button;
- turn off the ignition;
- disconnect the engine control unit wiring connector;
- check the wire to contact 2 of the four-pin connector of the engine control unit wiring for a short to contact 1 of the wire and to ground. Set the value: ∞ Ohm.
10. If no fault is found in the wires, then replace the engine control unit.
Continue testing at ambient temperature
11. Remove the intake air temperature sensor (the wiring connector remains connected) (Fig. 3.38).
12. Remember the temperature value in field 4 of the display.
13. Spray the sensor with cooling spray, watching the temperature reading. It should decrease slightly.
14 Click "→".
15. Press "06" to select the "Complete Output" function and confirm by pressing the "Q" button.
Visitor comments