System Inspection

SYSTEM INSPECTION
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 special service tool (SST) new generation star tester (NGS).
(2) Select the PID/DATA MONITOR AND RECORD function on the NGS display.
(3) By using the "FANCLNL", verify that the cooling fan control signal is OFF.
I. If the cooling fan control signal is ON, check the following.
^ ECM terminal voltage. Engine coolant temperature signal
II. If the cooling fan control signal is OFF, check the following.
^ Fan relay
^ Short circuit in wiring harnesses and connectors (Main relay - Fan relay - ECM)







5. Connect the special service tool (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 (SST-NGS).
(2) Select the SIMULATION TEST function on the NGS display.
(3) Turn the fan relay from OFF to ON by using the "FANCLNL" and check for the cooling fan operation.
I. If the cooling fan operates, check the following.
^ ECM terminal voltage
^ Diagnostic test mode signal
^ Closed throttle position signal
II. If the cooling fan does not operate, do as follows.
a. Turn the fan relay from OFF to ON by using the "FAN". Operate the fan relay and check if the operation sound of the relay is heard.
b. If the operation sound is heard, check the following.
^ Wiring harnesses and connectors
(Fan relay - Fan motor)
^ Fan motor
c. If the operation sound is not heard, check the following.
^ Fan relay
^ Open circuit in wiring harnesses and connectors (Main relay - Fan relay - ECM)