Inspection Procedure 4

The Immobilizer Indicator Light does not Illuminate.

The Security Indicator Circuit Part 1:

The Security Indicator Circuit Part 2:

CIRCUIT OPERATION
If the requirements for starting the engine are not satisfied, the immobilizer-ECU flashes the immobilizer indicator for 30 seconds.

TECHNICAL DESCRIPTION (COMMENT)
The immobilizer indicator light or a malfunction of the combination meter or immobilizer-ECU.

TROUBLESHOOTING HINTS
- Malfunction of combination meter
- Malfunction of immobilizer-ECU
- Damaged harness wires or connectors

DIAGNOSIS PROCEDURE

Required Special Tools:
- MB991223: Harness Set




STEP 1. Check immobilizer-ECU connector C-113 for loose, corroded or damaged terminals, or terminals pushed back in the connector

Q: Is immobilizer-ECU connector C-113 in good condition?

YES: Go to Step 2.

NO: Repair or replace the damaged component(s). Confirm that scan tool MB991958 communicates normally.




STEP 2. Check the immobilizer indicator light circuit of immobilizer-ECU connector C-113.
1. Disconnect the immobilizer-ECU C-113 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.




3. Connect terminal 5 to the ground.

Q: Does only the immobilizer indicator light illuminate? (other indicator lights are in good condition)

YES: Replace the immobilizer-ECU. Then register the password (secret code) and encrypted code.

NO: Go to Step 3.







STEP 3. Check immobilizer-ECU connector C-113 and combination meter connector C-05 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are immobilizer-ECU connector C-113 and combination meter connector C-05 in good condition?

YES: Go to Step 4.

NO: Repair or replace the damaged component(s). Confirm that scan tool MB991958 communicates normally.







STEP 4. Check the wiring harness between combination meter connector C-05 (terminal 20) and immobilizer-ECU connector C-113 (terminal 5).

Q: Is the wiring harness between combination meter connector C-05 (terminal 20) and immobilizer-ECU connector C-113 (terminal 5) in good condition?

YES: Go to Step 5.

NO: Repair the wiring harness. Check to see that all meters operate.




STEP 5. Measure the voltage at combination meter connector C-04 in order to check the battery circuit of power supply system to the combination meter.
1. Turn the ignition switch to the "OFF" (LOCK) position.
2. Disconnect combination meter connector C-04, and measure at the wiring harness side.




3. Measure the voltage between terminal 42 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES: Go to Step 8.

NO: Go to Step 6.




STEP 6. Check combination meter connector C-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is combination meter connector C-04 in good condition?

YES: Go to Step 7.

NO: Repair or replace the damaged component(s). Check to see that all meters operate.




STEP 7. Check the wiring harness between combination meter connector C-04 (terminal 42) and the battery.






NOTE: Also check junction block connector C-205, C-203 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-205, C-203 is damaged, repair or replace it.

Q: Is the wiring harness between combination meter connector C-04 (terminal 42) and the battery in good condition?

YES: Go to Step 8.

NO: Repair the wiring harness. Check to see that all meters operate.

STEP 8. Retest the system.

Q: Is the malfunction eliminated?

YES: The procedure is complete. (If no malfunctions are found in all steps, an intermittent malfunction is suspected.

NO: Go to Step 1.