Inspection Procedure 28

Radiator Fan, A/C Condenser 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 or short-circuited harness wire.
- ECM failed.
- PCM failed.

DIAGNOSIS

STEP 1. Measure the voltage at ECM connector C-51 or PCM connector C-52 .
1. Disconnect connector C-51 or C-52 and measure the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 18 and ground.
- Voltage should be between 4.8 and 5.2 volts. (Fan rotates at high speed.)

4. Connect a jumper cable between 18 and ground.
- Fan stops.

5. Turn the ignition switch to "LOCK" (OFF) position. If within specifications, go to Step 2.

If not within specifications, go to Step 3.

STEP 2. Check harness connector C-51 at the ECM or harness connector C-52 at the PCM for damage.
If harness connector C-51 or C-52 is not damaged, replace the ECM or PCM.

If harness connector C-51 or C-52 is damaged, repair or replace them. Refer to Harness Connector Inspection.
Then check that the malfunction is eliminated.

STEP 3. Check harness wire between fan controller connector A-30 and ECM connector C-51 or PCM connector C-52 .

NOTE: Check the wire after checking intermediate connector C-09. 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-51 or PCM connector C-52 is damaged, repair it.

If the wire between fan controller connector A-30 and ECM connector C-51 or PCM connector C-52 is not damaged, check the radiator fan and A/C compressor fan circuit. Refer to Engine Cooling Diagnosis - Symptom Chart.

Then check the malfunction is eliminated.