Inspection Procedure 16

CIRCUIT OPERATION
When the battery positive voltage from PCM (terminal number 75) is grounded at auto-cruise control-ECU (terminal number 3), the auto-cruise control-ECU emits a overdrive cancel signal. When a malfunction of the auto-cruise control circuit occurs, the transaxle may downshift harshly with the auto-cruise control engaged.

COMMENT
A malfunction may be present on the auto-cruise signal line circuit, auto-cruise control-ECU or the PCM.

TROUBLESHOOTING HINTS
The most likely causes for this cause:
- Damaged harness, connector
- Malfunction of the PCM
- Malfunction of the auto-cruise control-ECU

DIAGNOSIS
STEP 1. Check The Auto-Cruise Control System.
Check the auto-cruise control system. Refer to Auto-cruise Control System Diagnosis - Auto-cruise Control System Diagnostic Troubleshooting Strategy.
If the auto-cruise control system is operating properly, go to Step 2.
If the auto-cruise control system is not operating properly, repair it, then check the symptom.

STEP 2. Check The Auto-Cruise Control Signal Circuit.





1. Disconnect harness connector C-20 at auto-cruise control-ECU.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 3 and ground.
- Voltage should be battery positive voltage.
If battery positive voltage, replace auto-cruise control-ECU. Recheck the symptom. If symptom still exists, replace PCM. The immobilizer-ECU and the ignition key should be replaced together with it. Refer to Ignition Switch and Immobilizer System - Ignition Switch and Immobilizer System.
If not battery positive voltage, go to Step 3.

STEP 3. Check The Harness Connector C-57 <2.4L Engine> Or C-59 <3.0L Engine> At The PCM For Damage.





If the harness connector C-57 <2.4L Engine> or C-59 <3.0L Engine> is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check for the symptom.
If harness connector C-57 <2.4L Engine> or C-59 <3.0L Engine> is in god condition, go to Step 4.

STEP 4. Check The Harness Connector C-20 At The Auto-Cruise Control-ECU For Damage.





If the harness connector C-20 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check for the symptom.
If harness connector C-20 is in good condition, repair the harness wires or the connectors between the PCM and the auto-cruise control-ECU.