Electrical Fan Control System

1. Verify that the engine is cold.
2. Turn the ignition switch to ON.
3. Verify that the cooling fan is not operating.
4. If the cooling fan is operating, do as follows.
(1) Connect the SSTs (NGS).
(2) Select the PID/DATA MONITOR AND RECORD function on the NGS display.
(3) By using the "FANCN", verify that the cooling fan control signal is off.
(4) If the cooling fan control signal is on, check the PCM terminal voltage.
- Engine coolant temperature signal
(5) If the cooling fan control signal is off, check the following.
- Fan relay
- Short circuit in wiring harnesses and connectors (Main relay - Fan relay - PCM)
5. Connect the SST (System selector) and set system select switch to 1 and test switch to SELF TEST.
6. Depress the accelerator pedal and verify that the cooling fan operates.
7. If the cooling fan does not operate, do as follows.
(1) Connect the SSTs (NGS).
(2) Select the SIMULATION TEST function on the NGS display.
(3) Turn the fan relay from OFF to ON by using the "FANCN" and check for the cooling fan operation.
(4) If the cooling fan operates, check the following.
- PCM terminal voltage
- Diagnostic test mode signal
- Closed throttle position signal
(5) If the cooling fan does not operate, do as follows.
(1) Turn the fan relay from OFF to ON by using the simulation function. Operate the fan relay and check if the operation sound of the relay is heard.
(2) If the operation sound is heard, check the fan motor and related harness.
(3) If the operation sound is not heard, check the cooling fan relay and related harness.