Patriot 4WD L4-2.4L (2009)
Tests/PCM Verification Test
No
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Go to 4
4. ENGINE COOLANT TEMPERATURE SENSOR
NOTE: Allow the engine to cool to ambient temperature before proceeding.
WARNING: Make sure the engine cooling system is cool before removing the pressure cap or any hose. The cooling system is pressurized when
hot. Failure to follow these instructions can result in possible serious or fatal injury.
1. With the scan tool, read the Engine Coolant Temperature Sensor value for each sensor. If the engine was allowed to cool completely, the value
should be approximately equal to the ambient temperature.
2. Monitor each sensor value on the scan tool and the actual coolant temperature with a thermometer.
3. Start the engine.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not
wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
NOTE: The sensor value transition should be smooth as the engine reaches operating temperature. The thermometer reading and the coolant
temperature values on the scan tool should remain relatively close.
Were any problems found?
Yes
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Go to 5.
No
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Test complete.
5. ECT SIGNAL CIRCUIT HIGH RESISTANCE
NOTE: Perform this procedure for the sensor where erratic sensor values were detected in the previous test step.
1. Turn the ignition off.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in
poor terminal to pin connection. Install PCM Pinout Box 8815 along with the Adapter 8815-1 to perform the diagnosis.
2. Using a voltmeter, perform a voltage drop test by backprobing the ECT Signal circuit at the Engine Coolant Temperature Sensor harness
connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity
is displayed on the voltmeter.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not
wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
3. Start the engine.
Is the voltage below 0.5 volts?
Yes
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Go to 6
No
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Repair the ECT Signal circuit for excessive resistance.
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Perform the PCM Verification Test.See: Testing and Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Verification
Tests/PCM Verification Test
6. SENSOR GROUND CIRCUIT HIGH RESISTANCE
1. Turn the ignition off.
