Is there DTC(s) of ECT sensor circuit (DTC P0116 / P0117 /
P0118) and/or radiator cooling fan circuit (DTC P0480)?
Radiator cooling fan control circuit check
1) Connect scan tool to DLC with ignition switch turned
2) Start engine and select "Data List" on scan tool.
3) Warm up engine until coolant temp. is 100 °C, 212 °F or
higher and A/C switch turns OFF (if equipped with A/C).
(If engine coolant temp. dose not rise, check engine
cooling system or ECT sensor.)
Is radiator cooling fan started when engine coolant temp.
reached above temp.?
Radiator cooling fan control check
1) Disconnect radiator cooling fan motor connector with
ignition switch turned OFF.
2) Run engine when ECT is over 100 °C, 212 °F.
3) Measure voltage between vehicle body ground and
"BLU/RED" wire terminal of disconnected radiator
cooling fan motor connector.
Is voltage 10 – 14 V?
Check radiator cooling fan wire circuit check
1) Turn ignition switch to OFF position.
2) Measure resistance between "BLK" wire terminal of
disconnected radiator cooling fan motor connector and
vehicle body ground.
Is resistance below 1
Radiator cooling fan check
1) Check radiator cooling fan referring to "Radiator Cooling
Fan Assembly On-Vehicle Inspection in Section 1F".
Is it in good condition?
Idle Speed and IAC Throttle Valve Opening
Before idle speed check, make sure of the following.
• Lead wires and hoses of electronic fuel injection and
engine and emission control systems are connected
• Valve lash is checked according to maintenance
• Ignition timing is within specification.
• All accessories (wipers, heater, lights, A/C, etc.) are
out of service.
• Air cleaner has been properly installed and is in good
• No abnormal air drawn in from air intake system.
Engine General Information and Diagnosis:
Go to corresponding
Radiator cooling fan
control system is in
Go to Step 4.
Go to Step 5.
Substitute a known-
good ECM and recheck.
After all items are confirmed, check idle speed and IAC
throttle opening as follows.
Before starting engine, place transmission
gear shift lever in "Neutral", and set parking
brake and block drive wheels.
Go to Step 2.
Perform from Step 2 to
Step 7 in DTC P0480
diag. flow. If OK, Go to
"BLU/RED" wire is open
or high resistance
"BLK" wire is open or
high resistance circuit.
Faulty radiator cooling