Diagnostic Test

ACTIVE DTC
1. Turn the ignition off.
2. If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -64°C (83°F).
3. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
4. With the scan tool, select View DTCs.
  Is the DTC Active or Pending at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
ENGINE COOLANT TEMPERATURE
1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -64°C (83°F) until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With the scan tool, compare the AAT, ECT and Oil Temperature Sensor values.
  Is the Engine Coolant Temperature Sensor value within 10°C (18°F) of the other two sensor values?
  
  Yes
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
  No
  - Go To 3
EXCESSIVE RESISTANCE IN THE ECT SENSOR SIGNAL CIRCUIT
1. Turn the ignition off.
2. Using a Voltmeter, perform a voltage drop test. Back probe the (K2) ECT Sensor Signal circuit at the ECT Sensor harness connector and probe the appropriate terminal of the PCM C2 harness connector. Make sure the Voltmeter leads are connected so a 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 and allow it to reach normal operating temperature.
4. Monitor the Voltmeter.
  Is the voltage below 0.2 volts?
  
  Yes
  - Go To 4
  No
  - Repair the ECT Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Turn the ignition off.
2. Move the Voltmeter leads to back probe the (K900) Sensor Ground circuit at the ECT Sensor harness connector and probe the appropriate terminal of the PCM C2 harness connector. Make sure the Voltmeter leads are connected so a positive polarity is indicated 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 and allow it to reach normal operating temperature.
4. Monitor the Voltmeter.
  Is the voltage below 0.2 volts?
  
  Yes
  - Go To 5
  No
  - Repair the (K900) Sensor Ground circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
ENGINE COOLANT TEMPERATURE SENSOR
1. Turn the ignition off.
2. Replace the Engine Coolant Temperature Sensor.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -64°C (83°F).
6. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
7. With the scan tool, select View DTCs.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Repair complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the ECT Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the ECT Sensor and Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .