Inspection Procedure
1: Communication with the M.U.T.-III is not Possible.
COMMENTS ON TROUBLE SYMPTOM
If the system does not communicate with the M.U.T.-III, power supply to the diagnosis
connector or CAN bus lines may be defective.
PROBABLE CAUSE
Damaged harness wires and connectors
DIAGNOSIS PROCEDURE
STEP 1. Check that the engine-ECU <M/T> or
the engine-A/T-ECU <A/T> communicates with the M.U.T.-III.
Check that the M.U.T.-III communicates with the engine-ECU <M/T> or
the engine-A/T-ECU when the M.U.T.-III is operated.
Q.
Is the check result satisfactory?
Go to Step 2.
Diagnose the MPI system <3000 and 3800> or diesel fuel system <3200> (Refer
to GROUP 13A - Troubleshooting 
<3000>, GROUP
13B - Troubleshooting <3800> or
GROUP 13D - Troubleshooting <3200>).
STEP 2. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result satisfactory?
Diagnose the power supply circuit. Refer to .
Repair the CAN bus lines (Refer to GROUP 54D - Troubleshooting ).