Diagnostic Test

CHECK FOR AN ACTIVE DTC
NOTE:
Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.

NOTE:
After any repairs have been made, verify proper O2 Sensor operation. If all the O2 Sensor voltage readings have not returned to normal, follow the diagnostic procedure for the remaining O2 Sensors.
1. Start the engine.
2. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
3. With the scan tool, read DTCs and record on the repair order.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
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 exhaust leaks found?
  
  Yes
  - Perform the appropriate repairs.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT VOLTAGE
1. Turn the ignition off
2. Disconnect the O2 Sensor 1/2 Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K141) O2 Sensor 1/2 Signal circuit in the O2 Sensor 1/2 harness connector.
  Is the voltage between 4.1 and 5.0 volts?
  
  Yes
  - Go To 4
  No
  - Check the (K141) O2 Sensor 1/2 Signal circuit for a short to ground, open or short to voltage. If OK, replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K904) O2 SENSOR 1/2 RETURN CIRCUIT VOLTAGE
1. Measure the voltage on the (K904) O2 Sensor 1/2 Return circuit at the O2 Sensor 1/2 harness connector.
  Is the voltage at 2.5 volts?
  
  Yes
  - Go To 5
  No
  - Check the (K904) O2 Sensor 1/2 Return circuit for a short to ground, open or short to voltage. If OK, replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE O2 SENSOR FOR PROPER OPERATION
NOTE:
Check for signs of contaminants that may have damaged the O2 Sensor 1/2, such as contaminated fuel, unapproved silicone, oil and coolant.
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 Sensor 1/2 and the Powertrain Control Module (PCM).
  - Look for any chafed, pierced, pinched or partially broken wires.
  - Look for broken, bent, pushed out or corroded terminals.
  - Verify that there is good pin to terminal contact in the O2 Sensor 1/2 and Powertrain Control Module connectors.
  - Perform any Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the Oxygen Sensor 1/2 in accordance with the Service Information. Refer to SENSOR, OXYGEN, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .