Diagnostic Procedure
- STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES : Go to Step 3.
NO : Repair the CAN bus lines. (Refer to TROUBLESHOOTING .) After repairing the CAN bus line, go to Step 2.
- STEP 2. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES : Go to Step 3.
NO : This diagnosis is complete.
- STEP 3. Fluid check
Check that the fluid level is adequate. (Refer to ON-VEHICLE SERVICE .)
Q: Is the check result normal?
YES : Go to Step 4.
NO : Add the fluid. Then go to Step 14.
- STEP 4. Scan tool diagnostic trouble code
Check if the AWC diagnostic trouble code No. C1611, C1612, C1625, or C161D is set.(Refer to DIAGNOSTIC TROUBLE CODE CHART .)
Q: Is the DTC set?
YES : Perform the relevant troubleshooting.
NO : Go to Step 5.
- STEP 5. Scan tool actuator test
OK: Operating sound of the electric pump can be heard.
Q: Is the check result normal?
YES : Go to Step 13.
NO : Go to Step 6.
- STEP 6. Electric pump relay single unit check
Check the electric pump relay.(Refer to AWC SWITCH CHECK .)
Q: Is the check result normal?
YES : Go to Step 7.
NO : Replace the electric pump relay. (Refer to AWC-ECU .) Then go to Step 14.
- STEP 7. Electric pump relay connector check: A-26X
Q: Is the check result normal?
YES : Go to Step 8.
NO : Repair the defective connector. Then go to Step 14.
- STEP 8. Check the wiring harness between A-26X electric pump relay connector terminal No. 2 and fusible link (35).
Check the power supply line for short or open circuit.
Q: Is the check result normal?
YES : Go to Step 9.
NO : Repair the wiring harness. Then go to Step 14.
- STEP 9. Electric pump connector check: F-14
Q: Is the check result normal?
YES : Go to Step 10.
NO : Repair the defective connector. Then go to Step 14.
- STEP 10. Check the wiring harness between A-26X electric pump relay connector terminal No. 4 and F-14 electric pump connector terminal No. 2.
Check the power supply line for short or open circuit.
Q: Is the check result normal?
YES : Go to Step 11.
NO : Check C-21 and D-12 intermediate connectors. When no problem is found, repair the wiring harness. Then go to Step 14.
- STEP 11. Check the wiring harness between F-14 electric pump connector terminal No. 1 and body ground.
Check the ground line for open circuit.
Q: Is the check result normal?
YES : Go to Step 12.
NO : Repair the wiring harness. Then go to Step 14.
- STEP 12. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES : Replace the hydraulic unit. (Refer to HYDRAULIC UNIT .) Then go to Step 13.
NO : Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)
- STEP 13. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES : Replace the AWC-ECU.(Refer to AWC-ECU .) Then go to Step 14.
NO : This diagnosis is complete.
- STEP 14. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES : Return to Step 1.
NO : This diagnosis is complete.