Diagnostic Test

LOW COOLANT LEVEL
NOTE:
If any ECT or AAT DTCs are present, diagnose and repair those DTCs before continuing with this test procedure.

WARNING:
Never open the cooling system when the engine is hot. The system is under pressure. Failure to follow these instructions can result in personal injury including extreme burns, scalding, or fatal injury. Allow the engine to cool before opening the cooling system.
1. Check the cooling system to make sure that the coolant is in good condition and at the proper level. Refer to STANDARD PROCEDURE .
  Is the coolant level and condition OK?
  
  Yes
  - Go To 2
  No
  - Inspect the vehicle for a coolant leak and add the necessary amount of coolant. Refer to LEAK TESTING .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR HIGH RESISTANCE IN THE (K2) ECT SIGNAL CIRCUIT
1. Turn the ignition off.
2. Disconnect the ECT Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the ECT Signal circuit between the ECT Sensor harness connector and the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the ECT Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR HIGH RESISTANCE IN THE ECT SENSOR GROUND CIRCUIT
1. Measure the resistance of the ECT Sensor Ground circuit between the ECT Sensor harness connector and the PCM C2 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the ECT Sensor Ground for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE COOLING SYSTEM OPERATION
NOTE:
If engine coolant temperature is above 65°C (149°F), allow the engine to cool until it is below 65°C (149°F).
1. Start the engine.
2. Check for proper operation of the cooling system while the engine warms up toward operating temperature. 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.
  Were any issues found with the cooling system?
  
  Yes
  - Perform the appropriate repair in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
ENGINE COOLANT TEMPERATURE SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Replace the Engine Coolant Temperature Sensor in accordance with the Service Information. Refer to SENSOR, COOLANT TEMPERATURE, REMOVAL AND INSTALLATION .
4. Start the engine and allow it to idle for up to two minutes.
5. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Repair is complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK RELATED HARNESS 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 .