Inspection Procedure 1
SYMPTOM PROCEDURESInspection Procedure 1: The Diagnostic Trouble Code Is Not Set.
CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
Diagnosis Connector Communication Circuit (Part 1):
Diagnosis Connector Communication Circuit (Part 2):
TECHNICAL DESCRIPTION (COMMENT)
If neither normal nor abnormal DTC is set, the headlight automatic leveling-ECU, the headlight automatic leveling-ECU power supply, wiring harness or connectors of ground, or wiring harness and connectors between the headlight automatic leveling-ECU and date link connector may have a problem.
TROUBLESHOOTING HINTS
- Malfunction of the headlight automatic leveling-ECU
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
DIAGNOSIS
Required Special Tools:
- MB992006: Extra fine probe
- MB991223: Harness set
STEP 1. Check headlight automatic leveling-ECU connector C-110 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is headlight automatic leveling-ECU connector C-110 in good condition?
YES : Go to Step 2.
NO : Repair the damaged parts.
STEP 2. Resistance measurement at headlight automatic leveling-ECU connector C-110.
1. Disconnect the connector, and measure the resistance at the wiring harness-side connector.
2. Measure the resistance between headlight automatic leveling-ECU connector C-110 (terminal No. 14) and body ground.
The measured value should be continuity exists (2 ohms or less).
Q: Does the measured resistance value correspond with this range?
YES : Go to Step 4.
NO : Go to Step 3.
STEP 3. Check the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 14) and body ground.
Q: Is the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 14) and body ground. in good condition?
YES : Go to Step 4.
NO : Repair the wiring harness.
STEP 4. Voltage measurement at the C-110 headlight automatic leveling-ECU connector.
1. Disconnect the connector, and measure at the wiring harness-side connector.
2. Turn the ignition switch to the "ON" position.
3. Voltage between headlight automatic leveling-ECU connector (terminal No. 1) and body ground.
The voltage should measure approximately 12 volts (battery positive voltage).
Q: Does the voltage measure battery voltage?
YES : Go to Step 6.
NO : Go to Step 5.
STEP 5. Check the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 1) and fusible link (34).
NOTE: Before the wiring harness check, check the ETACS-ECU connectors C-309 and C-317, and the intermittent connector C-33. Then, repair them if necessary.
Q: Is the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 1) and the fusible link (34) in good condition?
YES : Go to Step 6.
NO : Repair the wiring harness.
STEP 6. Check data link connector C-125 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is data link connector C-125 in good condition?
YES : Go to Step 7.
NO : Repair the damaged parts.
STEP 7. Check the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 5/7) and data link connector C-125 (terminal No. 1/10).
NOTE: Before the wiring harness check, check the intermittent connector C-33 and C-34. Then, repair them if necessary.
Q: Is the wiring harness between headlight automatic leveling-ECU connector C-110 (terminal No. 5/7) and data link connector C-125 (terminal No. 1/10) in good condition?
YES : Go to Step 8.
NO : Repair the wiring harness.
STEP 8. Retest the system.
Check if DTC is set.
Q: Is the DTC set?
YES : Refer to diagnostic trouble code chart. Diagnostic Trouble Code Descriptions
NO : Replace the headlight automatic leveling-ECU.