Cooling System: Testing and 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.

New Generation Star (NGS) Tester, Connected to DLC-2:

(1) Connect the Special Service Tool (SST) New Generation Star (NGS) tester.
(2) By using the PID DATA MONITOR AND RECORD function, verify that the cooling fan control signal is OFF.
I. If the cooling fan control signal is ON, check the following.
- PCM 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 - PCM)

DLC-1 Connection For Electrical Fan Control System Testing:

5. Connect the data link connector terminals TEN and GND with a jumper wire.
6. Depress the accelerator pedal and verify that the cooling fan operates.
7. If the cooling fan does not operate, do as follows.
(1) Install the SSTs.
(2) Turn the fan relay from OFF to ON by using the SIMULATION TEST function and check for the cooling fan operation.
I. If the cooling fan operates, check the following.
- PCM 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 simulation function. 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 - PCM)