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Home >> Mitsubishi >> 2000 >> Galant ES L4-2350cc 2.4L SOHC MFI >> Repair and Diagnosis >> Powertrain Management >> Transmission Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Symptom Diagnosis Charts >> Inspection Procedure 16

Inspection Procedure 16

INSPECTION PROCEDURE 16: TRANSAXLE WON'T DOWNSHIFT UNDER LOAD WITH AUTO-CRUISE ENGAGED.





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 control 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.
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 for the symptom.

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





1. Disconnect harness connector C-52 at auto-cruise control-ECU.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 3 and ground. 9 Voltage should be battery positive voltage.
If battery positive voltage, replace auto-cruise control-ECU. Recheck the symptom. If symptom still exists, replace PCM. On 2000 models, the immobilizer-ECU should be replaced together with it. Refer to Ignition Switch and Immobilizer System.
If not battery positive voltage, go to Step 3.

STEP 3. Check The Harness Connector C-41 At The PCM For Damage.





If the harness connector C-41 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check for the symptom.
If harness connector C-41 is in good condition, go to Step 4.

STEP 4. Check The Harness Connector C-52 At The Auto-Cruise Control-ECU For Damage.





If the harness connector C-52 is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check for the symptom.
If harness connector C-52 is in good condition, repair the harness wires or the connectors between the PCM and the auto-cruise control-ECU.

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