Diagnostic Test

CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  Are there any O2 Sensor DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
  No
  - Go To 2
CHECK THE ENGINE COOLANT TEMPERATURE (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 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 Intake Air Temperature (IAT) Sensor and Ambient Air Temperature (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 3
  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. Refer to ENGINE SENSORS, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR AN ACTIVE DTC
1. With the scan tool, read DTCs and record on the repair order.
2. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
  Is the DTC active or pending?
  
  Yes
  - Go To 4
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
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
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
CHECK THE ETHANOL CONTENT IN THE FUEL
1. Perform the CHECKING FOR PROPER ETHANOL LEVEL IN THE GASOLINE test procedure. Refer to CHECKING FOR PROPER ETHANOL LEVEL IN THE GASOLINE .
  Were any issues found with the gasoline?
  
  Yes
  - Perform the appropriate repair in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
CHECK ENGINE MECHANICAL FOR PROPER OPERATION
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
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 7
CHECK THE UPSTREAM O2 SENSOR WIRING
1. Disconnect the Upstream O2 Sensor harness connector.
2. Disconnect the PCM C2 harness connector.
  CAUTION:
  Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
4. Check the Upstream O2 Sensor circuits;
  - for a short to ground in the wiring between the O2 Sensor harness connector and the PCM C2 harness connector.
  - for an open or high resistance in the wiring between the O2 Sensor harness connector and the PCM C2 harness connector.
  Were any problems found?
  
  Yes
  - Perform the appropriate repair.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 8
REPLACE THE OXYGEN SENSOR AND RETEST FOR DTC
1. Replace the Upstream O2 Sensor in accordance with the Service Information. Refer to ENGINE SENSORS, REMOVAL AND INSTALLATION .
2. Connect the Bank 1 Upstream O2 Sensor and PCM harness connectors.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Using the Freeze Frame Data or When Monitored Conditions above, operate the vehicle within the conditions that set the DTC.
  Did the DTC return?
  
  Yes
  - Go To 9
  No
  - Replacing the Upstream O2 Sensor repaired the fault.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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
  - 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 .