B1725

Symptom: If the turbo pressure signal sent to the instrument is faulty, the needle will remain at zero. If the turbo pressure signal between the pressure sensor and the engine management system is faulty, the CHECK ENGINE lamp (MIL) will light up.

B1725

Fault symptoms

If the turbo pressure signal sent to the instrument is faulty, the needle will remain at zero. If the turbo pressure signal between the pressure sensor and the engine management system is faulty, the CHECK ENGINE lamp (MIL) will light up.

Diagnostic procedure

1.	If the CHECK ENGINE lamp (MIL) is on, continue fault diagnosis as described under the Trionic , Motronic 2.10.1 or Motronic 2.8.1 engine management systems. If it does not, continue with point 2.

2.	Switch on the ignition.

3.	Connect the Scan Tool and select "READ VALUES" followed by "TURBO PRESSURE".

4.	If the system is OK, the Scan Tool's display should show 93- 105 kPa and the needle of the turbo/APC gauge should move to a position between the white and orange zones when the ignition is switched on. If the Scan Tool reading is not OK, continue with point 5.

5.	Check the wiring by connecting a BOB to the main instrument display panel's 56-pin connector and another BOB to the TRIONIC's 70-pin connector. The main instrument display panel and the TRIONIC control module should not be connected.

6.	Take a reading across pins 9 and 10 on the main instrument display panel and across pins 20 and 67 on the other BOB to check for an open circuit or short circuit.