Multiplex Control System Troubleshooting

Troubleshooting

MODE 1 Test
1. Remove the driver's dashboard lower cover.
2. Check the No. 9 (10 A) fuse in the under-hood fuse/relay box and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?

YES - Go to step 3.

NO - Find and repair the cause of the blown fuse.

3. Turn the ignition switch ON (II). If the driver's seat belt is unbuckled the seat belt reminder will chime 6 times.
4. Set the ceiling light to the center position and close all the doors.




5. Connect the special tool (A) to the multiplex inspection connector (B).
6. After about 5 seconds the spotlight and ceiling light should come on for 2 seconds, go out, then blink on for 0.2 second to show the system is now in mode 1.

Did the spotlight and ceiling light indicate mode 1?

YES - Go to step 8.

NO - Go to step 7.

7. Check for continuity between terminal 4 of the under-dash fuse/relay box connector J and body ground.

Is there continuity?

YES - Replace the under-dash fuse/relay box.

NO - Repair the open in the wire. If the wire is OK, repair G301.

8. If the DTCs are present, the spotlight and ceiling light will blink to indicate the DTC(s). If more than one DTC is present, the DTCs will be displayed in ascending order. If there are no DTCs the spotlight and ceiling light will not blink again after the Mode 1 indication.

Are there any DTCs?

YES - Go to step 9.

NO - Go to the Mode 2 test.







9. Troubleshoot the DTC(s) in the order indicated using the given charts.
If a faulty control unit is suspected, substitute it with a known food part and recheck for DTCs,
- If the DTC(s) is still present, go to the next step listed for the DTC.
- If the DTC(s) is no longer present replace the original part.

MODE 2 Test
1. From Mode 1, disconnect the special tool from the multiplex inspection connector for 5 to 10 seconds, and then reconnect it.
2. The spotlight and ceiling light should come on for 2 seconds, go out, then blink twice, 0.2 seconds each time. The system is now in Mode 2.




3. Operate the switches listed below: If the circuit is OK, the spotlight and ceiling light will blink once. If the circuit is faulty, the lights will not blink.
Tip: Operate the switches most closely related to the problem you are diagnosing is a quick way of testing the circuits integrity.

4. If all inputs were confirmed, or multiple circuits failed at the same time in Mode 2, go to the multiplex sleep mode test. If a single switch fails in Mode 2, troubleshoot its circuit.