[13B] MULTIPORT FUEL INJECTION (MPI) <4G64> - - TROUBLESHOOTING - SYMPTOM PROCEDURES - Inspection Procedure 28: A/C Load Signal System | PRINT PAGE / INDEX / PRIOR / NEXT

Inspection Procedure 28: A/C Load Signal System
OPERATION The A/C load signal is inputted to the engine-A/T-ECU (terminal No. 61) from the A/C-ECU (terminal No. 5).
FUNCTION The magnitude of the A/C compressor load is detected and input to the engine-A/T-ECU. The engine-A/T-ECU provides A/C idle up control according to the A/C compressor load condition.
PROBABLE CAUSE Failed A/C-ECU Open/short circuit in A/C load signal circuit or loose connector contact Failed engine-A/T-ECU
| DIAGNOSIS PROCEDURE
| STEP 1. Perform voltage measurement at C-111 engine-A/T-ECU connector.
| Measure engine-A/T-ECU terminal voltage. Engine: Idling A/C switch: ON (A/C compressor in driven state) Voltage between terminal No. 61 and earth. OK: 1 V or less (when the temperate around the atmospheric air temperature sensor is 18°C or more, and the A/C is set to the lowest temperature and the maximum air flow rate) System voltage (when the A/C is set to the temperature in the cabin and the minimum air flow rate) Q: Is the check result normal? YES: Go to Step 2 . NO: Go to Step 4 .
| STEP 2. Connector check: C-111 engine-A/T-ECU connector
| Q: Is the check result normal? YES: Go to Step 3 . NO: Repair.
| STEP 3. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace engine-A/T-ECU. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).
| STEP 4. Connector check: C-111 engine-A/T-ECU connector
| Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
| STEP 5. Perform voltage measurement at C-06 A/C-ECU connector.
| Measure A/C-ECU terminal voltage. Engine: Idling A/C set temperature: Maximum Cool when temperature in cabin is 25°C or more Maximum Hot when temperature in cabin is 25°C or less Voltage between terminal No. 5 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 8 . NO: Go to Step 6 .
| STEP 6. Connector check: C-06 A/C-ECU connector
| Q: Is the check result normal? YES: Go to Step 7 . NO: Repair.
| STEP 7. Check harness between C-06 (terminal No. 5) A/C-ECU connector and C-111 (terminal No. 61) engine-A/T-ECU connector.
| NOTE: Before checking harness, check intermediate connector C-104, and repair if necessary. Check output line for short circuit. Q: Is the check result normal? YES: Check A/C system (Refer to GROUP 55A - Troubleshooting ). NO: Repair.
| STEP 8. Connector check: C-06 A/C-ECU connector
| Q: Is the check result normal? YES: Check intermediate connector C-104, and repair if necessary. If intermediate connector is normal, check and repair harness between C-06 (terminal No. 5) A/C-ECU connector and C-111 (terminal No. 61) engine-A/T-ECU connector. Check output line for open circuit. NO: Repair.

[13B] MULTIPORT FUEL INJECTION (MPI) <4G64> - - TROUBLESHOOTING - SYMPTOM PROCEDURES - Inspection Procedure 28: A/C Load Signal System | PRINT PAGE / INDEX / PRIOR / NEXT

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