Communication With Scan Tool Is Not Possible (All Systems)

CIRCUIT OPERATION
- A battery positive voltage is applied on the data link connector power terminal (terminal 16). The ground terminals (terminal 4, 5) are grounded to the vehicle body.

COMMENT
- The cause is probably a defect in power supply system (including ground) for the on-board diagnostic test mode line.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the data link connector.
- Damaged harness wire.




WIRING DIAGRAM




CONNECTORS

DIAGNOSIS




STEP 1. Check the power supply line at the data link connector C-23.
1. Measure voltage between terminal 16 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
If within specifications, go to Step 2.
If not within specifications, check the intermediate connectors C-66, C-78 and C-85, and repair or replace if needed. Refer to Harness Connector Inspection >. If the intermediate connectors C-66, C-78 and C-85 are in good condition, repair the harness wire between the data link connector C-23 and fusible link (1).
Then confirm that the malfunction symptom is eliminated.




STEP 2. Check the ground line at the data link connector C-23.
1. Check for the continuity between terminal 4, 5 and ground.
- There should be continuity (0 Ohm).
If no continuity, repair the harness wire between the data link connector C-23 and the ground.
If continuity, replace the scan tool.
Then confirm that the malfunction symptom is eliminated.