P2246

P2246-O2 SENSOR 1/1, 2/1 REFERENCE VOLTAGE CIRCUIT HIGH





For a complete wiring diagram, refer to the Wiring Information.

Theory of operation

The Oxygen sensors (O2 Sensor) are used for fuel control and catalyst monitoring. Each O2 Sensor compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 Sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 Sensor heats the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 Sensor heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient O2 Sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 Sensor voltage to determine the air-to-fuel ratio. An O2 Sensor voltage that increases toward 1,000 mV indicates a rich fuel mixture. An O2 Sensor voltage that decreases toward 0 mV indicates a lean fuel mixture.

- When Monitored:
Engine running for 15 seconds, O2 Sensors at operating temperature and battery voltage greater 10.4 Volts.

- Set Condition:
The PCM detects that the (K902) Reference Signal voltage is greater than 3.9 Volts for nine seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, select View DTCs. Copy DTC and Freeze Frame information.
3. Start the engine.

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.

4. Allow the engine to reach normal operating temperature.
5. Monitor the scan tool for at least two minutes.
6. 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. Intermittent Condition Test

2. (K902) O2 SENSOR RETURN CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Disconnect the O2 Sensor 1/1 harness connector.
4. Disconnect the O2 Sensor 2/1 harness connector.
5. Turn the ignition on.
6. Measure the voltage of the (K902) O2 Sensor Return circuit reference voltage circuit at the O2 Sensor 1/1 or 2/1 harness connector.

Is there any voltage present?

Yes

- Repair the (K902) O2 Sensor Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. (K902) O2 SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE




1. Measure the resistance of the (K902) O2 Sensor Return circuit reference voltage circuit between the O2 Sensor 1/1 or 2/1 harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the (K902) 02 Sensor 1/1 or 2/1 Signal circuit for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. O2 SENSOR




1. Turn the ignition off.
2. Connect the PCM C2 harness connector.
3. Ignition on, engine not running.
4. With the scan tool, monitor the O2 Sensor 1/1 and 2/1 voltage.
5. Connect a jumper wire between the (K41) O2 Sensor 1/1 Signal circuit and the (K902) O2 Sensor Return circuit at the O2 Sensor 1/1 harness connector.
6. Repeat step 5 for the (K43) O2 Sensor 2/1 Signal circuit.

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

Yes

- Verify that there is good pin to terminal contact in the O2 Sensors and Powertrain Control Module connectors. Replace the O2 Sensor not indicating the specified voltage if no problems were found with the connections. Oxygen Sensor - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5
NOTE: Remove the jumper wire before continuing.


5. POWERTRAIN CONTROL MODULE
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen Sensors and the PCM.
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

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

No

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