77-1

VTM-4 DTC Troubleshooting: 77-1

DTC 77-1:

The Functional Abnormalities of Fuel Emission system or Automatic Transmission

NOTE: Before you troubleshoot, review the general troubleshooting information Initial Inspection and Diagnostic Overview.

1. Turn the ignition switch to ON (II).

2. Make sure the HDS communicates with the vehicle and the VTM-4 control unit. If it doesn't, troubleshoot the DLC circuit Testing and Inspection.

3. Clear the DTC with the HDS.

4. Start the engine.

5. Check for DTCs with the HDS.

Is DTC 77-1 indicated?

YES -

Go to step 6.

NO -

Intermittent failure, the system is OK at this time.�

6. Check for DTCs in the Fuel emission or Automatic Transmission system with the HDS.

Are any Fuel emission or Automatic Transmission system DTCs indicated?

YES -

Go to the indicated DTC's troubleshooting.�

NO -

Substitute a known-good VTM-4 control unit Service and Repair, and recheck. If the symptom/indication goes away with the known-good VTM-4 control unit, replace the original VTM-4 control unit Service and Repair.�