1. Communication With Scan Tool Is Not Possible (All Systems)

Auto-cruise Control-ECU Supply, Ground and Data Link Circuit:

Connectors C-101, C107:

CIRCUIT OPERATION
Power of the auto-cruise control-ECU is transmitted from the ignition switch (IG1) to the auto-cruise control-ECU through multi-purpose fuse 13 in the junction block.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably a malfunction of the auto-cruise control-ECU power supply circuit or the auto-cruise control-ECU ground circuit.

TROUBLESHOOTING HINTS
- Malfunction of the connector and harness.
- Malfunction of the auto-cruise control-ECU.

DIAGNOSIS




STEP 1. Check the auto-cruise control-ECU power supply circuit.
1. Disconnect C-20 connector at the auto-cruise control-ECU and measure at the harness side.
2. Measure the voltage between harness connector terminal 6 and ground.
- Ignition switch: "ON"
- Voltage should be system voltage.

If system voltage, go to Step 4.

If not system voltage, go to Step 2.







STEP 2. Check harness connectors C-101, C-107 at the junction block and C-20 at the auto-cruise control-ECU for damage.
If harness connectors C-20, C-101 and C-107 are damaged, repair or replace them. Then check that the malfunction is eliminated.
If the harness connectors are in good condition, go to Step 3.







STEP 3. Check the harness wires between auto-cruise control-ECU connector C-20 and junction block connector C-101.
If any harness wires between auto-cruise control-ECU connector C-20 and junction block connector C-101 are damaged, repair them. Then check that malfunction is eliminated.

NOTE: After checking intermediate connector C-107, inspect the wire. If intermediate connector C-107 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.




STEP 4. Check the auto-cruise control-ECU ground supply circuit.
1. Disconnect C-20 connector at the auto-cruise control-ECU and measure at the harness side.
2. Measure the continuity between harness connector terminals 14 and ground.
- Should be less than 2 ohms.

If the circuit is open, go to Step 5.

If less than 2 ohms, go to Step 7.




STEP 5. Check harness connector C-20 at the auto-cruise control-ECU for damage.
If harness connector C-20 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.
If the harness connector is in good condition, go to Step 6.




STEP 6. Check the harness wires between auto-cruise control-ECU connector C-20 and ground.
If any harness wires between auto-cruise control-ECU connector C-20 and ground are damaged, repair or replace them. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.
If harness connector C-20 is in good condition, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.







STEP 7. Check harness connector C-29 and data link connector C-20 at the auto-cruise control-ECU for damage.
If harness connectors C-20 and C-29 are damaged, repair or replace them. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.
If the harness connectors are in good condition, go to Step 8.







STEP 8. Check the harness wires between data link connector C-29 and auto-cruise control-ECU connector C-20.
If any harness wires between data link connector C-29 and auto-cruise control-ECU connector C-20 are damaged, repair or replace them. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.
If the harness wires are in good condition, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.