P2273

P2273-O2 SENSOR 2/2 SIGNAL STUCK RICH





For a complete wiring diagram refer to Diagrams/Electrical.


- When Monitored:

O2 Sensor Heater Temperature is greater than 496° C (925° F) and battery voltagegreater than 10.99 volts.

- Set Condition:

The Oxygen Sensor voltage is stuck rich for a calibrated amount of time. Two Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


Diagnostic Test


1. ACTIVE DTC

NOTE: When only one O2 Sensor is shorted to voltage, the scan tool will display all O2 Sensor voltage readings atapproximately 5.0 volts. When diagnosing this DTC, only diagnose the O2 Sensor that set the DTC.

Start the engine.

Allow the engine to reach normal operating temperature.

With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition


2. (K243) O2 2/2 SIGNAL CIRCUIT SHORTED TO VOLTAGE





Turn the ignition off.

Disconnect the PCM harness connectors

Disconnect the 2/2 O2 Sensor harness connector.

Measure the voltage on the (K243) O2 Sensor 2/2 Signal circuit in the O2 Sensor harness connector.


NOTE: Measure the voltage in reference to ground, not the (K904) O2 Return Downstream circuit.

Is there any voltage present?

Yes

- Repair the short to battery voltage in the (K243) O2 Sensor 2/2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3


3. (K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO VOLTAGE





Measure the voltage on the (K904) O2 Return Downstream circuit in the 2/2 O2 Sensor harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K904) O2 Return Downstream circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4


4. O2 SENSOR





Turn the ignition off.

Connect the PCM harness connectors.

Connect a jumper wire between the (K243) O2 2/2 Signal circuit and the (K904) O2 Return Downstream circuit in the 2/2 O2 Sensor harness connector.

Ignition on, engine not running.

With a scan tool, monitor the 2/2 O2 Sensor voltage.

Is the voltage between 2.3 and 2.7 volts with the jumper wire installed?

Yes

- Replace the O2 Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

NOTE: Remove the jumper wire before continuing.


5. (K243) O2 2/2 SIGNAL CIRCUIT OPEN





Turn the ignition off.

Disconnect the C1 PCM 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 Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K243) O2 2/2 Signal circuit from the O2 Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the open in the (K243) O2 2/2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


6. (K904) O2 RETURN DOWNSTREAM CIRCUIT OPEN





Measure the resistance of the (K904) O2 Return Downstream circuit from the O2 Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 7

No

- Repair the open in the (K904) O2 Return Downstream circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


7. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test