Diagnostic Test

ACTIVE DTC
1. Start the engine and allow it to idle for at least 60 seconds. Allow the engine to run long enough for the O2 Sensor to enter closed loop operation.
  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 the active DTCs.
  Is the DTC Active at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the O2 Sensor 1/2 harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K141) O2 Sensor 1/2 Signal circuit at the O2 Sensor 1/2 harness connector.
  NOTE:
  Measure the voltage in reference to ground, not the (K904) O2 Sensor 1/2 Return circuit.
  
  Is the voltage reading above 5.0 volts?
  
  Yes
  - Repair the short to voltage in the (K141) O2 Sensor 1/2 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (K904) O2 SENSOR 1/2 RETURN CIRCUIT FOR A SHORT TO VOLTAGE
1. Measure the voltage on the (K904) O2 Sensor Return circuit at the O2 Sensor harness connector.
  Is the voltage reading above 5.0 volts?
  
  Yes
  - Repair the short to voltage in the O2 Return Downstream circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 4
O2 SENSOR
1. With the scan tool, monitor the O2 Sensor 1/2 voltage.
2. Connect a jumper between the (K141) O2 Sensor 1/2 Signal circuit and the (K904) O2 Sensor Return circuit at the O2 Sensor 1/2 harness connector.
  Is the voltage between 2.3 and 2.7 volts with the jumper in place?
  
  Yes
  - Verify that there is good pin to terminal contact in the O2 Sensor 1/2 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 .
  No
  - Go To 5
    NOTE:
    Remove the jumper wire before continuing.
CHECK THE (K141) O2 SENSOR 1/2 SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance of the (K141) O2 Sensor 1/2 Signal circuit between the O2 Sensor 1/2 harness connector and the PCM C1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the O2 Sensor 1/2 Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE O2 SENSOR 1/2 RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K904) O2 Sensor 1/2 Return circuit between the O2 Sensor 1/2 harness connector and the PCM C1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the (K904) O2 Sensor Return 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 Oxygen Sensor 1/2 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 and Powertrain Control Module harness 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 .