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Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    NOTE:

    It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

    Did the DTC return?

    Yes 

    • Go To  2

    No 

  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any other O2 Sensor DTCs active or pending?

      Yes 

      No 

      • Go To  3
  3. CHECK THE ECT SENSOR FOR PROPER OPERATION 
    NOTE:

    This test works best if performed on a cold engine (cold soak).

    1. Turn the ignition on.
    2. With the scan tool, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit overnight (cold soak), the temperature value should be a sensible value that is somewhere close to the ambient temperature.
    3. Compare the ECT Sensor value with the IAT Sensor and AAT Sensor values.
      NOTE:

      If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is reached.

    4. Start the engine and allow it to idle.
    5. During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth transition from start up to normal operating temperature 82°C (180°F). The value should reach at least 82°C (180°F).

      Is the ECT Sensor value within a reasonable range with the other sensors at ignition on and did the ECT value increase smoothly and did it reach at least 82°C (180°F)?

      Yes 

      • Go To  4

      No 

      • Verify that there is good pin to terminal contact in the Engine Coolant Temperature Sensor and Powertrain Control Module connectors. If OK, replace the Engine Coolant Temperature Sensor.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE O2 SENSOR HEATER FOR PROPER OPERATION 
    1. Turn the ignition off.
      NOTE:

      Wait a minimum of 10 minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize at 5.0 volts.

    2. Turn the ignition on.
    3. With the scan tool, actuate the O2 Sensor 1/1 Heater Test.
    4. With the scan tool, monitor O2 Sensor 1/1 voltage for at least two minutes.

      Does the voltage stay above 4.5 volts?

      Yes 

      • Verify that there is good pin to terminal contact in the O2 Sensor and Powertrain Control Module connectors. If no problems are found, replace the O2 Sensor.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE O2 SENSOR FOR PROPER OPERATION 
    1. Start the engine.
    2. With the scan tool, monitor the O2 Sensor 1/1 reading.

      Is the voltage switching between 2.5 and 3.4 volts?

      Yes 

      • Go To  6

      No 

      • Check the O2 Sensor terminals for pushed out, corroded or spread terminals and verify that the wires for the O2 Sensor are not open or shorted to ground. If no problems are found, replace the O2 Sensor.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE MAP SENSOR FOR PROPER OPERATION 
    1. Turn the ignition off.
    2. Connect a Vacuum Gauge to a Manifold Vacuum source.
    3. Start the engine.
    4. Allow the engine to idle.
      NOTE:

      If engine will not idle, maintain a constant rpm above idle.

    5. With the scan tool, read the MAP Sensor vacuum value.

      Is the scan tool reading within one inch of Hg as compared to the Vacuum Gauge reading?

      Yes 

      • Go To  7

      No 

      • Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. If OK, replace the MAP Sensor.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK THE FUEL DELIVERY SYSTEM FOR PROPER OPERATION 
    1. Perform the CHECKING THE FUEL DELIVERY SYSTEM test procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .

      Were any problems found?

      Yes 

      No 

      • Go To  8
  8. CHECK THE ENGINE FOR MECHANICAL PROBLEMS 
    1. Turn the ignition off.
    2. Check for any of the following conditions/mechanical problems:
      • AIR INDUCTION SYSTEM - must be free from leaks
      • ENGINE VACUUM - must be at least 13 inches in neutral
      • ENGINE VALVE TIMING - must be within specifications
      • ENGINE COMPRESSION - must be within specifications
      • ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks
      • ENGINE PCV SYSTEM - must flow freely
      • TORQUE CONVERTER STALL SPEED - must be within specifications
      • POWER BRAKE BOOSTER - no internal vacuum leaks
      • FUEL - must be free of contamination
      • FUEL INJECTOR - plugged or restricted injector, control wire not connected to correct injector

      Are there any engine mechanical problems?

      Yes 

      No 

      • Go To  9
  9. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. 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.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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