Inspection Procedure 3: Back-Up Light Does Not Illuminate
INSPECTION PROCEDURE 3: Back-up light does not illuminate.
CAUTION
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
COMMENTS ON TROUBLE SYMPTOM
The back-up light, ETACS-ECU, or shift lever-ECU may have a problem.
PROBABLE CAUSES
^ Malfunction of the ETACS-ECU
^ Malfunction of the back-up light
^ Damaged harness wires and connectors
^ Malfunction of the shift lever-ECU
DIAGNOSTIC PROCEDURE
Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A
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 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.
STEP 2. Scan tool actuator test
Item No.2: Back-up light (Special Function (Actuator Test Reference Table))
Q: Is the check result normal?
YES: Intermittent malfunction.
NO: Go to Step 3.
STEP 3. Scan tool diagnostic trouble code
Check the ETACS diagnostic trouble code. (Diagnostic Trouble Code Descriptions)
Q: Is the DTC set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 4.
STEP 4. Bulb check
Check if the bulb of the back-up light which does not illuminate is normal.
Q: Is the check result normal?
YES: Go to Step 5.
NO: Replace the bulb which does not illuminate.
STEP 5. Measure the resistance at F-08 back-up light (RH) connector and F-22 back-up light (LH) connector.
Disconnect the connector of the light which does not illuminate, and measure the resistance between the connector terminal No. 2 and ground at the wiring harness side.
OK: Continuity exists. (2 ohms or less)
Q: Is the check result normal?
YES: Go to Step 8.
NO: Go to Step 6.
STEP 6. Inspection of the back-up light (RH) connector, back-up light (LH) connector, and intermediate connector: F-08, F-22, F-27
Check for the contact with the connector terminals of the light which does not illuminate.
Q: Is the check result normal?
YES: Go to Step 7.
NO: Repair the defective connector.
STEP 7. Check the wiring harness between F-08 back-up light (RH) connector terminal No. 2 and body ground, and between F-22 back-up light (RH) connector terminal No. 2 and body ground.
Check the ground harness of the light which does not illuminate for open circuit.
Q: Is the check result normal?
YES: Intermittent malfunction.
NO: Repair the wiring harness.
STEP 8. Measure the voltage at F-08 back-up light (RH) connector and F-22 back-up light (LH) connector.
1) Disconnect the connector of the light which does not illuminate, and measure the voltage between the connector terminal No. 3 and ground at the wiring harness side.
2) Turn the ignition switch to the "ON" position.
3) Place the shift lever to the R range.
OK: Battery positive voltage
Q: Is the check result normal?
YES: Intermittent malfunction.
NO: Go to Step 9.
STEP 9. Inspection of J/C (4), intermediate connector, shift lever assembly connector, ETACS-ECU connector, and back-up light connector: C-43, C-47, C-27, C-304, C-311, C-313, D-17, F-08, F-22, F27
Check for the contact with the connector terminals of the light which does not illuminate.
Q: Is the check result normal?
YES: Go to Step 10.
NO: Repair the defective connector.
STEP 10. Check the wiring harness between F-08 back-up light (RH) connector terminal No. 3 and C-313 ETACS-ECU connector terminal No. 4, and between F-22 back-up light (RH) connector terminal No. 3 and C-313 ETACS-ECU connector terminal No. 4.
Check the power supply line of the light which does not illuminate for open or short circuit.
Q: Is the check result normal?
YES: Go to Step 11.
NO: Repair the wiring harness.
STEP 11. Retest the system.
Q: Does a malfunction take place again?
YES: Replace the shift lever assembly.
NO: Intermittent malfunction.