[Previous][Next]
Inspection Procedure 1: The front 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.
 
 
 
 
TROUBLE JUDGMENT
The ETACS-ECU illuminates and extinguishes the front room light in accordance with the input signals below.
  • Ignition switch (IG1)
  • Key reminder switch
  • Door switches
  • Liftgate latch switch
  • Front door lock actuator (driver’s side)
 
 
TECHNICAL DESCRIPTION (COMMENT)
If this does not work normally, the above switch input circuit(s), front dome light, or ETACS-ECU may have a problem.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the key reminder switch
  • Malfunction of door switch
  • Malfunction of liftgate latch switch
  • Malfunction of the front door lock actuator (driver’s side)
  • Malfunction of front dome light
  • Malfunction of the ETACS-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. Rear dome light operation check.
Check that the rear dome light illuminates and extinguishes normally.
Does rear dome light work normally?
Go to Step 2.
Go to Step 9.
 
STEP 2. Using scan tool MB991958, read the diagnostic trouble code.
(1)
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect scan too (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Check whether the ETACS-ECU related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Diagnose the ETACS-ECU. Refer to ETACS, Diagnosis .
Go to Step 3.
 
STEP 3. Using scan tool MB991958, check data list.
Use the ETACS-ECU data list to check the signals related to the front dome light.
  • Turn the ignition switch to the "LOCK" (OFF) position.
  • Remove the ignition key from the ignition key cylinder.
  • Open each door.
 
Item No.Item nameNormal condition
Item 228Dr door unlockON
Item 254IG voltage1 V or less
Item 256Dr door ajar switchOpen
Item 257As door ajar switchOpen
Item 258RR door ajar switchOpen
Item 259RL door ajar switchOpen
Item 260Trunk/gate trunk ajar switchOpen
Item 264Handle lock switchKey in → Key out
Does scan tool MB991958 display the items "Dr door unlock", "IG voltage", "Dr door ajar switch", "As door ajar switch", "RR door ajar switch", "RL door ajar switch" and "Handle lock switch" as normal condition?
(Normal conditions are displayed for all items.) Go to Step 4.
(Normal condition is not displayed.) Troubleshoot the ETACS-ECU. Refer to ETACS, Diagnosis, Input signal chart .
 
STEP 4. Check front dome light connector E-09 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is front dome light connector E-09 in good condition?
Go to Step 5.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 5. Front dome light and bulb check
Check that the front dome light and bulb is normal.
Is front dome light and bulb normal?
Go to Step 6.
Replace the front dome light or bulb.
 
STEP 6. Check ETACS-ECU connector C-416 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is ETACS-ECU connectors C-416 in good condition?
Go to Step 7.
Repair or replace the damaged component(s). Refer to GROUP 00E, Harness Connector Inspection .
 
STEP 7. Check the wiring harness between front dome light connector E-09 (terminal 2, 3) and ETACS-ECU connector C-416 (terminal 6, 5)
  • Check the signal line for open circuit and short circuit.
Are wiring harness between front dome light connector E-09 (terminal 2, 3) and ETACS-ECU connector C-416 (terminal 6, 5) in good condition?
Go to Step 8.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 8. Check the wiring harness between front dome light connector E-09 (terminal 1) and body ground.
  • Check the ground wires for open circuit.
Is wiring harness between front dome light connector E-09 (terminal 1) and body ground in good condition?
Replace the front dome light, and then go to Step 9.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 9. Retest the system
Check that the front dome light illuminates and extinguishes normally.
Do the front dome light work 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.