Bosch

TESTING PROCEDURE:

NOTE: While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Use the wiring diagrams found in CHASSIS ELECTRICAL DIAGRAMS to supplement your testing efforts.

Color Code Legend:

Checking ECU Ground Connections:

1. Turn ignition OFF.
2. Access fuel injection ECU by removing the passenger side kick panel and glove compartment.
3. Check fuel injection ECU ground connections. They should make good contact and fit tight.

Removing ECU Connector:

4. Remove fuse #1 (located in central electric unit behind ash tray) to interrupt the power supply. Then remove the ECU connector by pressing up the latch and folding out the wire cluster.

Removing Protective Sleeve:

5. Remove connector protective sleeve and reinstall fuse #1 for testing.
CAUTION: ^ Never check connections from the front. Connectors can get damaged and worsen the problem.
^ Check connections through the holes in the connector.
^ Connection pin numbers are printed on the connector side.

Checking Pin 35:

6. Turn ignition ON.
7. Connect a voltmeter between pin 35 at ECU connector and ground (checking ignition switch).

Reading: 12 volts

8. If not, check wiring, fuses #12 #13 (located behind center console ash tray) and connectors. If no fault found, replace ignition switch and retest.
9. Crank starter motor.

Reading: 12 volts

If not, check wiring and connectors. If no fault found, replace ignition switch and retest.
10. Turn ignition OFF.

Checking Ground Connections:

11. Connect an ohmmeter between pin 5 and ground.

Reading: 0 ohm

12. If not, check wiring and fix as necessary.
13. Then connect the ohmmeter between pin 17 and ground.

Reading: 0 ohm

14. If not, check wiring and fix as necessary.
15. Then connect the ohmmeter between pin 19 and ground.

Reading: 0 ohm

16. If not, check wiring and fix as necessary.
17. Then connect the ohmmeter between pin 29 and ground.

Reading: 0 ohm

18. If not, check wiring and fix as necessary.
19. Disconnect the test equipment. Remove the #1 fuse and reconnect the ECU and all other connectors, install the kick panel and glove compartment. Ensure that the rubber seal in the ECU connector is installed before it is connected to the unit.
20. Reinstall the #1 fuse.
21. The previous tests eliminate any power supply or ECU ground problems. If an ECU fault is suspected, go by the FLOW OF DIAGNOSIS or see step 22.
22. To find the problem, you can test every input and output device. If no faults are found and all wiring, connectors, fuses and the battery are in good condition, replace and retest ECU with known good unit.