INSPECTION
PROCEDURE 8: A/C-ECU power supply system
|
COMMENTS ON TROUBLE SYMPTOM
|
|
If the auto A/C controller assembly (A/C-ECU) is not energised, the power supply or earth
system to the ECU may be defective.
|
|
- Malfunction of the A/C-ECU.
- Damaged wiring harness or connectors
|
|
STEP 1. M.U.T.-III other system’s diagnosis code
|
|
Check that the ETACS-ECU has not stored a diagnosis code.
|
|
Q.
Is the diagnosis code stored?
|
|
Carry out the diagnosis code procedures. Refer to GROUP 54A, ETACS-ECU .
|
|
|
|
Go to Step 2.
|
|
|
|
STEP 2. Measure the voltage at the auto A/C controller assembly (A/C-ECU)
connector.
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
(2)Voltage between terminal No. 20 and body earth OK: System voltage
|
|
Q.
Is the check result normal?
|
|
Go to Step 3.
|
|
|
|
Go to Step 4.
|
|
|
|
STEP 3. Check open circuit in IG2 line between IG (2) relay and A/C
controller assembly (A/C-ECU) connector.
|
|
note |
Before the wiring harness check, check the junction block connector.
|
|
|
Q.
Is the check result normal?
|
|
Intermittent malfunction (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
|
|
|
|
Repair the connector(s) or wiring harness.
|
|
|
|
STEP 4. Measure the resistance at the auto A/C controller assembly
(A/C-ECU) connector.
|
|
(1)Disconnect the connector, and measure at the wiring harness side.
|
|
(2)Resistance between terminal No. 19 and body earth OK: Continuity exists (2 Ω
or less)
|
|
Q.
Is the check result normal?
|
|
Replace the auto A/C controller assembly (A/C-ECU).
|
|
|
|
Go to Step 5.
|
|
|
|
STEP 5. Check open circuit in E line between auto A/C controller assembly
(A/C-ECU) connector and body earth.
|
|
Q.
Is the check result normal?
|
|
Intermittent malfunction (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
|
|
|
|
Repair the wiring harness.
|
|
|