[Previous][Next]
Inspection Procedure 1: The dome light does not illuminate normally.
 
 
cautionWhenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
OPERATION
The ETACS-ECU illuminates and extinguishes the dome light in accordance with the input signals below.
  • Ignition switch (IG1)
  • Key reminder switch
  • Door switches
  • Front door lock actuator (driver’s side)
 
 
TECHNICAL DESCRIPTION (COMMENT)
If this does not work normally, the above switch input circuit(s), dome light assembly, or ETACS-ECU may have a problem.
 
 
TROUBLESHOOTING HINTS
  • The key reminder switch may be defective
  • The door switch may be defective
  • The front door lock actuator (driver’s side) may be defective
  • The dome light assembly may be defective
  • The ETACS-ECU may be defective
  • 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. Retest the system.
At which switch positions (DOOR or ON), the dome light does not illuminate?
The light does not illuminate at both the DOOR and ON positions. : Go to Step 2.
The light does not illuminate at the ON position. : Go to Step 4.
The light does not illuminate at the DOOR position. : Go to Step 6.
 
STEP 2. Dome light bulb check
Check that the dome light bulb is normal.
Is the check result normal?
Go to Step 3.
Replace the dome light bulb.
 
STEP 3. Check of short to power supply, and open circuit in output lines between the dome light connector and the fusible link.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 4. Check of open circuit in ground line between the dome light connector and the ground.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Retest the system
Check that the dome light illuminates/extinguishes normally.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the dome light assembly.
 
STEP 6. Using scan tool (M.U.T.-III), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect Scan Tool (M.U.T.-III) ."
(2) Use the ETACS-ECU service data to check the signals related to the operation of dome light.
  • Turn the ignition switch to the LOCK (OFF) position.
  • Remove the ignition key from the ignition key hole.
  • Open each door.
 
Item No.Item nameNormal condition
19Driver's door switchON
20Driver's door unlock switchON
28Steering lock switchOFF → ON
30Ignition switch (IG1)OFF
48Passenger's door switchON
49Rear door switchON
OK: Normal conditions are displayed for all the items.
Is the check result normal?
Go to Step 7.
Troubleshoot the ETACS-ECU. Refer to ETACS, Diagnosis, Input Signal Chart .
 
STEP 7. Check of open circuit in ROOM LP lines between the dome light connector and the ETACS-ECU connector.
Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.
 
STEP 8. Retest the system
Check that the dome light illuminates/extinguishes normally.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.