Symptom Troubleshooting

Advanced Hydraulic Booster Symptom Troubleshooting - AHB indicator does not go off, and no DTCs are stored

AHB indicator does not go off, and no DTCs are stored

1. Turn the ignition switch to LOCK (0).

2. Check the No. 63 (15 A) fuse in the auxiliary under-hood fuse/relay box.

Is the fuse blown?

YES -

Go to step 3.

NO -

Reinstall the checked fuse, then go to step 8.

3. Disconnect the servo unit 25P connector Service and Repair.

4. Check for continuity between servo unit 25P connector terminal No. 8 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire between the No. 63 (15 A) fuse and the servo unit.�

NO -

Install a new No. 63 (15 A) fuse in the auxiliary under-hood fuse/relay box, then go to step 5.

5. Reconnect the servo unit 25P connector.

6. Turn the ignition switch to ON (II).

7. Check the AHB indicator for several seconds when the ignition switch is turned to ON (II).

Does the indicator come on then go off?

YES -

Troubleshooting is complete.�

NO -

Replace the servo unit Service and Repair.�

8. Disconnect the servo unit 25P connector Service and Repair.

9. Measure the voltage between servo unit 25P connector terminal No. 8 and body ground.





Is there battery voltage?

YES -

Go to step 10.

NO -

Repair an open in the wire between the No. 63 (15 A) in the auxiliary under-hood fuse/relay box and the servo unit.�

10. Check the No. 4 (7.5 A) fuse in the under-dash fuse/relay box.

Is the fuse blown?

YES -

Go to step 11.

NO -

Reinstall the checked fuse, then go to step 15.

11. Check for continuity between servo unit 25P connector terminal No. 16 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire between the No. 4 (7.5 A) fuse and the servo unit.�

NO -

Install a new No. 4 (7.5 A) fuse in the under-dash fuse/relay box, then go to step 12.

12. Reconnect the servo unit 25P connector.

13. Turn the ignition switch to ON (II).

14. Check the AHB indicator for several seconds when the ignition switch is turned to ON (II).

Does the indicator come on then go off?

YES -

Troubleshooting is complete.�

NO -

Replace the servo unit Service and Repair.�

15. Turn the ignition switch to ON (II).

16. Measure the voltage between servo unit 25P connector terminal No. 16 and body ground.





Is there battery voltage?

YES -

Go to step 17.

NO -

Repair an open in the wire between the No. 4 (7.5 A) in the under-dash fuse/relay box and the servo unit.�

17. Turn the ignition switch to LOCK (0).

18. Check the No. 36 (10 A) fuse in the under-dash fuse/relay box.

Is the fuse blown?

YES -

Go to step 19.

NO -

Reinstall the checked fuse, then go to step 24.

19. Disconnect the buzzer 2P connector Service and Repair.

20. Check for continuity between servo unit 25P connector terminal No. 6 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire between the No. 36 (10 A) fuse or the buzzer and the servo unit.�

NO -

Install a new No. 36 (10 A) fuse in the under-dash fuse/relay box, then go to step 21.

21. Reconnect all connectors.

22. Turn the ignition switch to ON (II).

23. Check the AHB indicator for several seconds when the ignition switch is turned to ON (II).

Does the indicator come on then go off?

YES -

Troubleshooting is complete.�

NO -

Replace the servo unit Service and Repair.�

24. Turn the ignition switch to ON (II).

25. Measure the voltage between servo unit 25P connector terminal No. 6 and body ground.





Is there battery voltage?

YES -

Go to step 26.

NO -

Repair an open in the wire between the No. 36 (10 A) in the under-dash fuse/relay box and the servo unit.�

26. Turn the ignition switch to LOCK (0).

27. Check for continuity between body ground and servo unit 25P connector terminals No. 7, No. 23, and No. 24 individually.





Is there continuity?

YES -

Replace the servo unit Service and Repair.�

NO -

Repair an open in the wire between the servo unit and body ground (G202).�