TECHNICAL DESCRIPTION (COMMENT)
- This malfunction may be caused by a defective immobilizer-ECU, engine-A/T-ECU, or a defect in the communication line between the immobilizer-ECU and engine-A/T-ECU. If this malfunction appears when the MPI system and MUT-II/III can communicate each other, MPI system diagnosis code 54 will reset.
- If the MPI system is normal, the engine control relay can be determined as normal. In addition, if the MPI system and MUT-II/III can communicate each other, the circuits between the diagnosis connector and the engine-A/T-ECU can determined as normal.
NOTE: If this malfunction appears, MPI system diagnosis code 54 will be output.
TROUBLESHOOTING HINTS
- Malfunction of the immobilizer-ECU
- Malfunction of the engine-A/T-ECU
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
DIAGNOSIS PROCEDURE
STEP 2. Measure the voltage at immobilizer-ECU connector C-304-1.
- Disconnect immobilizer-ECU connector C-304-1.
- Turn the ignition switch to the "ON" position.
- Measure the voltage between terminal 1 and earth.
OK: Battery positive voltage
Q: Is the check result normal?
YES:
Go to Step 5
.NO: Go to Step 3
.STEP 3. Connector check: Immobilizer-ECU connector C-304-1 and engine
control relay connector B-17X.
Q: Are immobilizer-ECU connector C-304-1 and engine control relay connector B-17X in
good condition?
YES:
Go to Step 4.NO: Repair or replace the damaged component(s). Confirm that MUT-II/III communicates normally.
STEP 4. Check the harness wires between immobilizer-ECU connector
C-304-1 (terminal 1) and engine control relay connector B-17X (terminal 1).
NOTE: Prior to the wiring harness inspection, check intermediate connector C-106, joint connector
C-17 and key reminder switch connector C-304, and repair if necessary.
Q: Are the harness wires between immobilizer-ECU connector C-304-1 (terminal 1) and engine
control relay connector B-17X (terminal 1) in good condition?
YES:
There is no action to be taken.NO: Replace damaged component(s). Confirm that MUT-II/III communicates normally.
STEP 7. Check the harness wire between immobilizer-ECU connector C-304-1
(terminal 4) and earth.
NOTE: Prior to the wiring harness inspection, check key reminder switch connector C-304, and
repair if necessary.
Q: Is the harness wire between immobilizer-ECU connector C-304-1 (terminal 4) and earth
in good condition?
YES:
There is no action to be taken.NO: Repair or replace the damaged component(s). Confirm that MUT-II/III communicates normally.
STEP 8. Connector check: Immobilizer-ECU connector C-304-1 and engine-A/T-ECU
connector C-109.
Q: Are immobilizer-ECU connector C-304-1 and engine-A/T-ECU connector C-109
in good condition?
YES:
Go to Step 9.NO: Repair or replace the damaged component(s). Confirm that MUT-II/III communicates normally.
STEP 9. Check the harness wires between immobilizer-ECU connector
C-304-1 (terminal 3) and engine-A/T-ECU connector C-109 (terminal 111).
NOTE: Prior to the wiring harness inspection, check key reminder switch connector C-304, intermediate
connector C-104, and repair if necessary.
Q: Are the harness wires between immobilizer-ECU connector C-304-1 (terminal 3) and engine-A/T-ECU connector
C-109 (terminal 111) in good condition?
YES:
Go to Step 10.NO: Repair or replace the damaged component(s). Confirm that MUT-II/III communicates normally.
STEP 10. Replace the immobilizer-ECU or engine-A/T-ECU.
Q: Did the communication with the MUT-II/III become possible after replacing the immobilizer-ECU
or the engine-A/T-ECU?
YES:
Register the password (secret code) and encrypted code 
.
Confirm that MUT-II/III communicates normallyNO: Go to Step 11
.STEP 11. Recheck for malfunction.
Q: Is a malfunction eliminated?
YES:
The procedure is complete. (If no malfunctions are found in all steps, an intermittent
malfunction is suspected. Refer to GROUP 00, How to Use Troubleshooting/Inspection
Service Points -
How to Cope with Intermittent Malfunction ).NO: Replace the immobilizer-ECU or engine-A/T-ECU.