Inspection Procedure 29

Radiator Fan, A/c Condensor Fan Circuit:

CIRCUIT OPERATION
- The ECM or 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 five 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 circuit or short-circuited harness wire.
- ECM failed .
- PCM failed .

DIAGNOSIS

STEP 1. Measure voltage at ECM connector C49 or PCM connector C-50 .
1. Disconnect connector C-49 or C-50 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure voltage between terminal 21 or 18 and ground.
- Voltage should be between 4.8 and 5.2 volts (The fan rotates at a high speed).

4. Connect a jumper cable between 21 or 18 and ground.
- The fan should stop.

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

If the fan stops, go to Step 2.

If the fan does not stop, go to Step 3.

STEP 2. Check harness connector C-49 at the ECM or harness connector C-50 at the PCM for damage.
If harness connector C-49 or C-50 is not damaged, replace the ECM or PCM .

If harness connector C-49 or C-50 is damaged, repair or replace it. Refer to Harness Connector Inspection.
Then check that the malfunction is eliminated.

STEP 3. Check the harness wire between fan controller connector A-30 and ECM connector C49 or PCM connector C-50 .

NOTE: Check the wire after checking intermediate connector C-07 If intermediate connector C-07 is damaged, repair or replace it. refer to Harness Connector Inspection. Then check that the malfunction is eliminated.

If the wire between fan controller connector A-30 and ECM connector C-49 or PCM connector C-50 is not damaged, check the radiator fan and A/C condenser fan circuit. Refer to Diagnosis - Engine Cooling Diagnosis - Symptom Chart.

If the wire between Fan controller connector A-30 and ECM connector C-49 or PCM connector C-50 is damaged, repair it.

Then check that the malfunction is eliminated.