Diagnostic Test

CHECK THE COOLING SYSTEM FOR PROPER LEVEL AND CONDITION
WARNING:
Never open the cooling system when the engine is hot. The system is under pressure. Extreme burns or scalding may result. Failure to follow these instructions can result in possible serious or fatal injury. Allow the engine to cool before opening the cooling system.
1. Inspect the cooling system for proper level and condition.
  Is the coolant level and condition OK?
  
  Yes
  - Go To 2
  No
  - Inspect the vehicle for a coolant leak, make the appropriate repairs and add the correct amount of coolant. Refer to COOLING SYSTEM LEAKS .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE THERMOSTAT FOR PROPER OPERATION
NOTE:
For optimal test results, allow the vehicle to sit outside long enough to cool to ambient temperature in order to start the test with a totally cold soaked engine. With the scan tool, read the Engine Coolant Temperature degree value. If the engine was allowed to sit (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.
1. Turn the ignition on.
2. If engine coolant temperature is above 82°C (180°F), allow the engine to cool until it reaches at least 65°C (150°F) or cooler before continuing with this test.
3. Start the engine.
4. During engine warm-up monitor the Engine Coolant Temperature degree value on the scan tool. The temperature value change should be a smooth transition from start up to normal Thermostat opening temperature. Also monitor the actual coolant temperature with a digital thermometer at or near the ECT Sensor and Thermostat positions.
  NOTE:
  As the engine warms up to operating temperature, the actual coolant temperature (thermometer reading) and the scan tool Engine Coolant Temperature degree values should stay relatively close to each other. A discrepancy may indicate an inaccurate ECT Sensor signal to the PCM.
5. As the engine warms to operating temperature, record the temperature at which the Thermostat opens.
6. Using the appropriate Service Information, determine the proper opening temperature of the thermostat.
  Did the thermostat open at the proper temperature?
  
  Yes
  - Go To 3
  No
  - Replace the Thermostat in accordance with the Service Information. Refer to THERMOSTAT, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE ECT SENSOR FOR PROPER OPERATION
Was the digital thermometer readings relatively close to the scan tool reading for the ECT Sensor during warm up and when the Thermostat opened?

Yes
- Go To 4
No
- Replace the Engine Coolant Temperature (ECT) Sensor in accordance with the Service Information. Refer to ENGINE SENSORS, REMOVAL AND INSTALLATION .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE RADIATOR FOR RESTRICTIONS
NOTE:
The engine must be running and the Thermostat open to perform this test.
1. Check and compare the temperatures at the inlet and outlet of the Radiator. Check for proper operation of the entire cooling system. Be certain to check the Radiator Cap, flow through the Radiator and anything that can cause a lack of system pressure or lack of coolant flow in the system.
  NOTE:
  It is normal to see a lower temperature on the outlet of the Radiator, however a very large difference indicates a restriction in the Radiator core. This can cause this DTC to set due to the position on the ETC Sensor in the system. If necessary, compare the temperature difference with a similar vehicle.
  
  Was the difference in the temperature readings relatively larger than expected?
  
  Yes
  - Replace the Radiator in accordance with the Service Information. Refer to RADIATOR, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Disconnect all PCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .