Diagnostic Test
- 1) DTC IS ACTIVE NOTE: If an O2 sensor signal circuit is shorted to voltage, all O2 sensor voltage readings displayed on the scan tool will be approximately 5.0 volts. Diagnose the sensor that set the most current DTC.NOTE: After repairs have been completed, verify proper O2 Sensor operation. If all O2 Sensor voltage readings have not returned to normal, perform the diagnostic procedure for the remaining O2 Sensors.NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.
Start the engine and allow it to reach 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 can result in personal injury or death.With a scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go to 2).
No
- Refer to *CHECKING FOR AN INTERMITTENT DTC .
- 2) CHECKING THE EXHAUST SYSTEM FOR LEAKS
Perform the diagnostic procedure for *CHECKING THE EXHAUST SYSTEM FOR LEAKS .
Were any problems found?
Yes
- Repair as necessary.
- Perform *PCM VERIFICATION TEST .
No
- Go to 3).
- 3) (K43) O2 2/1 SIGNAL CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the 2/1 Oxygen Sensor harness connector.
Disconnect the Powertrain Control Module (PCM) harness connector.
Turn the ignition on.
Measure the voltage of the (K43) O2 2/1 Signal circuit in the 2/1 Oxygen Sensor harness connector.
NOTE: Measure the voltage in reference to ground, not the (K902) O2 Return (Up) circuit.Is there any voltage present?
Yes
- Repair the (K43) O2 2/1 Signal circuit for a short to voltage.
- Perform *PCM VERIFICATION TEST .
No
- Go to 4).
- 4) (K902) O2 RETURN (UP) CIRCUIT SHORTED TO VOLTAGE
Measure the voltage of the (K902) O2 Return (Up) circuit in the 2/1 Oxygen Sensor harness connector.
Is there any voltage present?
Yes
- Repair the (K902) O2 Return (Up) circuit for a short to voltage.
- Perform *PCM VERIFICATION TEST .
No
- Go to 5).
- 5) (K43) O2 2/1 SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Measure the resistance between ground and the (K43) O2 2/1 Signal circuit in the 2/1 Oxygen Sensor harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the (K43) O2 2/1 Signal circuit for a short to ground.
- Perform *PCM VERIFICATION TEST .
No
- Go to 6).
- 6) (K902) O2 RETURN (UP) CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K902) O2 Return (Up) circuit in the 2/1 Oxygen Sensor harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the (K902) O2 Return (Up) circuit for a short to ground.
- Perform *PCM VERIFICATION TEST .
No
- Go to 7).
- 7) (K43) O2 2/1 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
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 Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (K43) O2 2/1 Signal circuit between the 2/1 Oxygen Sensor harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go to 8).
No
- Repair the (K43) O2 2/1 Signal circuit for an open circuit or high resistance.
- Perform *PCM VERIFICATION TEST .
- 8) (K902) O2 RETURN (UP) CIRCUIT OPEN OR HIGH RESISTANCE
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 Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (K902) O2 Return (Up) circuit between the 2/1 Oxygen Sensor harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go to 9).
No
- Repair the (K902) O2 Return (Up) circuit for an open circuit or high resistance.
- Perform *PCM VERIFICATION TEST .
- 9) 2/1 OXYGEN SENSOR NOTE: Check for signs of contaminants that may have damaged the O2 Sensor, such as contaminated fuel, unapproved silicone, oil and coolant.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the 2/1 Oxygen Sensor 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.
Refer to any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform *PCM VERIFICATION TEST .
No
- Replace the 2/1 Oxygen Sensor in accordance with the Service Information.
- Perform *PCM VERIFICATION TEST .