Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.

STEP 1. Check whether the diagnostic trouble code is reset.
As for vehicles under low temperature condition, carry out the contents of the precautions, and then check the diagnostic trouble code again.

Q: Is diagnosis code No. C161E set?
1. YES: Go to Step 2.
2. NO: This diagnosis is complete.
STEP 2. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q: Is the check result normal?
1. YES: Go to Step 4.
2. NO: Repair the CAN bus lines. (Refer to TROUBLESHOOTING .) After repairing the CAN bus line, go to Step 3.
STEP 3. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
1. YES: Go to Step 4.
2. NO: This diagnosis is complete.
STEP 4. Fluid check
Check that the fluid level is adequate. (Refer to ON-VEHICLE SERVICE .)

Q: Is the check result normal?
1. YES: Go to Step 5.
2. NO: Add the fluid. Then go to Step 15.
STEP 5. 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?
1. YES: Perform the relevant troubleshooting.
2. NO: Go to Step 6.
STEP 6. Scan tool actuator test
OK: Operating sound of the electric pump can be heard.

Q: Is the check result normal?
1. YES: Go to Step 14.
2. NO: Go to Step 7.
STEP 7. Electric pump relay single unit check
Check the electric pump relay. (Refer to AWC SWITCH CHECK .)

Q: Is the check result normal?
1. YES: Go to Step 8.
2. NO: Replace the electric pump relay. (Refer to AWC-ECU .) Then go to Step 15.
STEP 8. Electric pump relay connector check: A-26X
Q: Is the check result normal?
1. YES: Go to Step 9.
2. NO: Repair the defective connector. Then go to Step 15.
STEP 9. 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?
1. YES: Go to Step 10.
2. NO: Repair the wiring harness. Then go to Step 15.
STEP 10. Electric pump connector check: F-14
Q: Is the check result normal?
1. YES: Go to Step 11.
2. NO: Repair the defective connector. Then go to Step 15.
STEP 11. 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?
1. YES: Go to Step 12.
2. NO: Check C-21 and D-12 intermediate connectors. When no problem is found, repair the wiring harness. Then go to Step 15.
STEP 12. 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?
1. YES: Go to Step 13.
2. NO: Repair the wiring harness. Then go to Step 15.
STEP 13. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
1. YES: Replace the hydraulic unit. (Refer to HYDRAULIC UNIT .) Then go to Step 14.
2. NO: Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .
STEP 14. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
1. YES: Replace the AWC-ECU. (Refer to AWC-ECU .) Then go to Step 15.
2. NO: This diagnosis is complete.
STEP 15. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
1. YES: Return to Step 2.
2. NO: This diagnosis is complete.