Diagnostic Test

ECT SENSOR
1. Turn the ignition on, engine not running.
2. With the scan tool, read ECT Sensor voltage.
3. Carefully tap on or near the ECT Sensor while monitoring the ECT Sensor voltage reading on the scan tool.
  NOTE:
  The sensor voltage should not change more than 0.5 volts.
  
  Does the voltage change more than 0.5 volts?
  
  Yes
  - Verify that there is good pin to terminal contact in the ECT Sensor and Powertrain Control Module connectors. If OK, replace the Engine Coolant Temperature Sensor. Refer to SENSOR, COOLANT TEMPERATURE, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 2
CHECK THE (K2) ECT SIGNAL CIRCUIT FOR AN INTERMITTENT SHORT TO VOLTAGE
NOTE:
This DTC will set due to an intermittent condition. Due to this condition it is recommended to wiggle test the wiring related to the ECT Sensor during testing in all of the following steps.
1. Turn the ignition off.
2. Disconnect the ECT Sensor harness connector.
3. Turn the ignition on, engine not running.
4. Measure the voltage on the (K2) ECT Sensor Signal circuit at the ECT Sensor harness connector.
  Is the voltage reading above 5.2 volts at any time while wiggle testing the harness?
  
  Yes
  - Repair the (K2) ECT Sensor Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (K2) ECT SIGNAL CIRCUIT FOR AN INTERMITTENT OPEN
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance of the (K2) ECT Sensor Signal circuit between the ECT Sensor harness connector and the PCM C2 harness connector.
  Does the resistance go above 5.0 Ohms at any time while wiggle testing the harness?
  
  Yes
  - Go To 4
  No
  - Repair the (K2) ECT Sensor Signal circuit for an intermittent open circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN INTERMITTENT OPEN
1. Measure the resistance of the (K900) Sensor Ground circuit from the ECT Sensor harness connector to the appropriate terminal of the PCM harness connector.
  Does the resistance go above 5.0 Ohms at any time while wiggle testing the harness?
  
  Yes
  - Go To 5
  No
  - Repair the (K900) Sensor ground circuit for an intermittent open circuit.
  - 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 .