Inspection Procedure 27

INSPECTION PROCEDURE 27: Fans (radiator fan, A/C condenser fan) are inoperative

Radiator Fan, A/C Condenser Fan Circuit:

CIRCUIT OPERATION
- The PCM sends a duty signal to the fan controller according to engine coolant temperature, vehicle speed, and the condition of the A/C switch. (The closer the average voltage at the terminal comes to 5 volts, the higher the fan speed becomes.)

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Malfunction of the fan motor relay.
- Malfunction of the fan motor.
- Malfunction of the fan controller.
- Improper connector contact, open or short-circuited harness wire.
- PCM failed.

DIAGNOSIS




STEP 1. Check harness connector B-18 at PCM for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 2.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.

STEP 2. Measure the output voltage at PCM harness side connector B-18.




1. Disconnect the B-18 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal No.10 and ground.
- Voltage should be between 4.9 and 5.1 volts. (Fan rotates at high speed.)

4. Connect a jumper cable between terminal No. 10 and ground.
- The fan should stop.

5. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Are the measured voltage and fan condition normal?

YES: Replace the PCM. When the PCM is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table. Then confirm that the malfunction symptom is eliminated.

NO: Go to Step 3.







STEP 3. Check for open circuit and short circuit to ground and harness damage between fan controller A-23 (terminal No. 2) and PCM connector B-18 (terminal No. 10).

Q: Is the harness wire in good condition?

YES: Refer to Engine Cooling Diagnosis - Symptom Chart.

NO: Repair it. Then confirm that the malfunction symptom is eliminated.