Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Start the engine and allow it to reach normal operating temperature.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
2. With the scan tool, read DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Oxygen Sensor 1/1 harness connector.
3. 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.
4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
5. Check for continuity of the (K79) O2 Sensor 1/1 Heater Control circuit between the Oxygen Sensor 1/1 harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the (K79) O2 Sensor 1/1 Heater Control circuit for an open circuit or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (Z909) GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Check for continuity between battery (-) and the (Z909) Ground circuit in the O2 Sensor 1/1 harness connector.
  NOTE:
  A good chassis ground can also be used in place of the battery (-).
  
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (Z909) Ground circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
OXYGEN SENSOR 1/1
1. Connect the Powertrain Control Module (PCM) C2 harness connector.
2. Turn the ignition on.
3. With the scan tool, actuate the Oxygen Sensor 1/1 control to the maximum allowable percentage.
4. Using a 12-volt test light connected to ground, check the (K79) O2 Sensor 1/1 Heater Control circuit in the Oxygen Sensor 1/1 harness connector.
  NOTE:
  The test light should flash dimly.
5. With the scan tool, actuate the Oxygen Sensor 1/1 control to the OFF (0%) position.
6. Using a 12-volt test light connected to ground, check the (K79) O2 Sensor 1/1 Heater Control circuit in the Oxygen Sensor 1/1 harness connector.
  NOTE:
  The test light should not be illuminated.
  
  Does the test light flash dimly with the actuator ON (25%) and not illuminated with the actuator OFF (0%)?
  
  Yes
  - Replace the Oxygen Sensor 1/1 in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 5
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensor 1/1 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.
4. Perform any Service Bulletins (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 and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .