Diagnostic Test

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, select View DTCs.
  Is the status Active for this DTC?
  
  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 A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Oxygen Sensor 1/1 harness connector.
3. Disconnect the Powertrain Control Module (PCM) C2 harness connector.
4. Measure the resistance between ground and the (K79) O2 Sensor 1/1 Heater Control circuit in the Oxygen Sensor 1/1 harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the (K79) O2 Sensor 1/1 Heater Control circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT SHORTED TO THE (Z909) GROUND CIRCUIT
1. Measure the resistance between the (K79) O2 Sensor 1/1 Heater Control circuit and the (Z909) Ground circuit in the Oxygen Sensor 1/1 harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the short between the (K79) O2 Sensor 1/1 Heater Control circuit and the (Z909) Ground circuit.
  - 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 OFF (0%).
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 with the control actuated OFF (0%).
  
  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. Refer to SENSOR, OXYGEN, REMOVAL .
  - 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 Technical Service Bulletins (TSBs) 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 .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .