Diagnostic Test

O2 SENSOR HEATER OPERATION
1. Turn the ignition off.
  NOTE:
  Wait a minimum of eight minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize between 4.6 and 5.0 volts.
2. Ignition on, engine not running.
3. With the scan tool, actuate the O2 Sensor 1/1 Heater Test.
4. Using the scan tool, monitor O2 Sensor 1/1 voltage for at least two minutes.
  Does the voltage stay above 4.5 volts?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
O2 SENSOR HEATER ELEMENT
1. Turn the ignition off.
  NOTE:
  Allow the O2 sensor to cool down to room temperature.
2. Disconnect the O2 Sensor harness connector.
3. Measure the resistance of the Heater Element through the O2 Sensor. Measure at the (F344) Fused ASD Relay Output terminal and the (K79) O2 Sensor Heater Control terminal of the O2 Sensor 1/1 connector.
  NOTE:
  The O2 Heater Element resistance values should be measured at 21.1°C (70 F). The resistance value will vary with different temperature values.
  
  Is the resistance of the O2 Sensor Heater Element between 2.0 and 30.0 Ohms?
  
  Yes
  - Go To 3
  No
  - Verify that there is good pin to terminal contact in the O2 Sensor and Powertrain Control Module connectors. If OK, replace the O2 Sensor. Refer to SENSOR, OXYGEN, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K79) O2 SENSOR 1/1 HEATER CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Disconnect the PCM C1 harness connector.
2. Measure the resistance of the (K79) O2 Sensor 1/1 Heater Control circuit between the O2 Sensor harness connector and the of PCM C1 harness connector.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K79) O2 Sensor 1/1 Heater Control circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (F344) FUSED ASD RELAY OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Remove the ASD Relay from the PDC.
2. Measure the resistance of the (F344) Fused ASD Relay Output circuit between the O2 Sensor harness connector and the ASD Relay Output terminal in the PDC.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the excessive resistance in the (F344) Fused ASD Relay Output circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K41) O2 SENSOR 1/1 SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Disconnect the PCM C1 harness connector.
2. Measure the resistance of the (K41) O2 Sensor 1/1 Signal circuit between the O2 Sensor harness connector and the of PCM C1 harness connector.
  Is the resistance below 0.5 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (K41) O2 Sensor 1/1 Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 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. Verify that there is good pin to terminal contact in the O2 Sensor 1/1 and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there 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 in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .