[13A] MULTIPORT FUEL INJECTION (MPI) <4G63> - - TROUBLESHOOTING - SYMPTOM PROCEDURES - Inspection Procedure 21: Abnormal Rotation of Fan Motor | PRINT PAGE / INDEX / PRIOR / NEXT

Inspection Procedure 21: Abnormal Rotation of Fan Motor
OPERATION The control (duty) signal is inputted to the fan controller (terminal No. 2) from the engine-A/T-ECU (terminal No. 18).
FUNCTION The engine-A/T-ECU inputs a duty signal suitable for the engine coolant temperature, vehicle speed and A/C switch position to the fan controller. In response to the signal, the fan controller controls the rotating speeds of the radiator fan and A/C condenser fan. (The fan speed becomes higher as the average voltage of the terminal comes nearer to 5 V.)
PROBABLE CAUSE Failed fan controller Open/short circuit in fan controller circuit or loose connector contact Failed engine-A/T-ECU
| DIAGNOSIS PROCEDURE
| STEP 1. Connector check: C-112 engine-A/T-ECU connector
| Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
| STEP 2. Check at C-112 engine-A/T-ECU connector.
| Disconnect connector, and measure at harness side. Ignition switch: ON Short-circuit terminal No.18 to earth. OK: Fan motor stops rotating. Q: Is the check result normal? YES: Go to Step 3 . NO: Go to Step 4 .
| 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. Perform voltage measurement at C-112 engine-A/T-ECU connector.
| Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 18 and earth. OK: 4.7 - 5.1 V Q: Is the check result normal? YES: Replace fan controller. NO: Go to Step 5 .
| STEP 5. Connector check: A-20 fan controller connector
| Q: Is the check result normal? YES: Go to Step 6 . NO: Repair.
| STEP 6. Check harness between A-20 (terminal No. 2) fan controller connector and C-112 (terminal No. 18) engine-A/T-ECU connector.
| NOTE: Before checking harness, check intermediate connector A-14, and repair if necessary. Check output line for open circuit. Q: Is the check result normal? YES: Replace fan controller. NO: Repair.

[13A] MULTIPORT FUEL INJECTION (MPI) <4G63> - - TROUBLESHOOTING - SYMPTOM PROCEDURES - Inspection Procedure 21: Abnormal Rotation of Fan Motor | PRINT PAGE / INDEX / PRIOR / NEXT

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