Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read DTCs and record on the repair order.
2. With the scan tool, record the related Freeze Frame data.
3. Start the engine. With the scan tool, verify that the fuel system is in closed loop fuel control.
4. Using the recorded data along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read DTCs.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
NOTE:
While this fault could set due to a faulty O2 Sensor or wiring, it is more likely to set due a mechanical, fuel or air handling issue. If the vehicle exhibits any fuel system or driveability issues, or has any other fuel or air handling system DTCs (I.E. O2 Sensor circuit, MAP Sensor, Fuel Injector, Ignition Coil, etc.), diagnose and repair those concerns before proceeding with this test.
1. Refer to the recorded DTCs.
  Are there any fuel or air handling system DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE MAP SENSOR OPERATION
1. Perform the CHECKING THE MAP SENSOR OPERATION test procedure. Refer to CHECKING THE MAP SENSOR OPERATION .
  Were any problems found?
  
  Yes
  - Perform the appropriate repair in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
ENGINE MECHANICAL
1. Turn the ignition off.
2. Check for any of the following conditions:
  - AIR INDUCTION SYSTEM - must be free from leaks.
  - ENGINE VACUUM LEAKS- check the entire engine and any vacuum lines/hoses for leaks.
  - POWER BRAKE BOOSTER - check for internal vacuum leaks. Monitor the engine speed and vacuum while pinching the vacuum hose going to the Brake Booster.
  - FUEL INJECTOR - if a Fuel Injector is suspected of being plugged or restricted, remove the fuel rail with the injectors intact. Energize the fuel pump to maintain fuel pressure in the fuel rail. Actuate the suspect Fuel Injector(s) with the scan tool and inspect the fuel spray pattern. Compare with the other injectors.
  - ENGINE PURGE FLOW SYSTEM - must flow freely with no leaks or restrictions. Check the hose and connections between the Purge Solenoid and the Intake Manifold.
  - ENGINE COMPRESSION - must be within specifications.
  Are there any engine mechanical problems present?
  
  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
CHECK THE FUEL DELIVERY SYSTEM
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 in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
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 7
CHECK THE EXHAUST SYSTEM FOR LEAKS
1. Perform the CHECKING THE EXHAUST SYSTEM FOR LEAKS test procedure. Refer to CHECKING THE EXHAUST SYSTEM FOR LEAKS .
  Were any problems found?
  
  Yes
  - Perform the appropriate repair in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 8
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 9
CHECK THE OXYGEN SENSOR OPERATION
1. Perform the CHECKING THE OXYGEN SENSOR OPERATION test procedure. Refer to CHECKING THE OXYGEN SENSOR OPERATION .
  Were any problems found?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 10
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 .