Cooling Fan Control System Inspection

COOLING FAN OPERATION




COOLING FAN
1. Verify the engine is cold.
2. Turn the ignition switch ON.
3. Verify the cooling fan is not operating.
4. If the cooling fan is operating:
(1) Connect the NGS tester to the DLC.
(2) Select the "ACTIVE COMMAND" then "OUTPUT TEST MODE" function on the NGS tester display.
(3) Select the "ALL OFF" and verify the cooling fan signal is OFF.
(4) If the cooling fan control signal is ON check:
- Cooling fan relay stuck in closed position.
- Short to ground circuit between cooling fan relay and PCM.
- Short to power in circuit between cooling fan relay.
- DTCs for ECT sensor.
- P0117,P0118,P0125,P1116,P1117.
(5) If the cooling fan is OFF, check the following.
- Short to ground circuit between A/C switch and PCM.
- DTC for ECT sensor.
- P0117,P0118,P0125,P1116,P1117.
5. Start the engine.
6. Verify that the cooling fan is operating when engine is hot.
7. If the cooling fan does not operate, do as follows.
(1) Connect the SSTs (NGS tester) to the DLC.
(2) Select "Active Command" mode.
(3) Select "Output Test Mode".
(4) Select "ALL ON" mode.
(5) Press "Start".
(6) If the cooling fan operates, check the ECT sensor DTCs. P0117,P0118,P0125,P1116,P1117.
(7) If the cooling fan does not operate, do as follows.
(1) Select "ALL ON". Operate cooling fan by selecting "Start" and verify that operational sound is heard from the cooling fan relay.
(2) If the operational sound is heard, check the wiring harnesses and connectors and cooling fan motor.
(3) If operational sound is heard, check cooling fan relay and open circuit in wiring harnesses and connectors.
8. Turn the A/C switch and fan switch ON.
9. Verify the cooling fan is operating.
10. If fan does not operate, check A/C system.




CONDENSER FAN RELAY
1. Verify that A/C switch and fan switch are OFF.
2. Start the engine and let it idle.
3. Verify that the condenser fan is not operating.
4. If condenser fan is operating, check:
- Condenser fan relay for stuck in closed position.
- Short to power in circuit between condenser fan relay and condenser fan.
- Short to ground in circuit between A/C pressure switches and PCM.
- Short to ground circuit between condenser fan relay and PCM terminal 17 (short circuit).
5. Turn the A/C switch and fan switch ON.
6. Verify that the condenser fan is operating and operating sound of A/C compressor magnetic clutch is heard.
7. Turn the A/C switch and fan switch OFF.
8. If the condenser fan does not operate but operating sound of A/C compressor magnetic clutch is heard, check as follows:
- Open circuit between ignition switch and condenser fan relay.
- Open circuit between battery and condenser fan relay.
- Open circuit between condenser fan relay and PCM.
- Open circuit between condenser fan relay and condenser fan motor or fan motor ground.
- Condenser fan relay stuck to open.
- Condenser fan motor.
9. If both condenser fan and A/C compressor do not operate, check:
- Throttle Position Sensor Voltage PID.