How severe is this DTC?
Excessive voltage in the O2 sensor reference voltage circuit can lead to reduced fuel efficiency and decreased engine performance. A P2246 code should be classified as severe and addressed as quickly as possible.
What are some symptoms of the code?
Symptoms of a P2246 fault code may include:
- Reduced fuel efficiency
- Decreased engine performance
- Stored misfire codes or lean/rich exhaust codes
- Service engine soon light illumination
What are some common causes of the code?
Causes
of this code may include:
- Blown O2 sensor fuse
- Faulty oxygen sensor(s)
- Burned, chafed, broken, or disconnected wiring and/or connectors
What are the troubleshooting steps for P2246?
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P2246 code.
You can save time by searching for technical service bulletins (TSBs) that match the recorded code, vehicle (year, make, model, and engine), and presented symptoms. This information can be found in your vehicle information source. If you find the right TSB, it might provide a quick solution to your diagnosis.
After connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and relevant freeze frame data, note the information (in case the code turns out to be intermittent). After that, clear the codes and test the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.
The code may be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P2246 to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, proceed with the diagnosis.
You can obtain connector face views, connector pinout charts, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the code and vehicle in question) using your vehicle information source.
Perform a visual inspection of the associated wiring and connectors. Repair or replace wiring that has been cut, burned, or damaged.
Use the DVOM to test the O2 sensor voltage at the appropriate connector pin (near the sensor). If no voltage is detected, check the system fuses. Replace blown or faulty fuses as needed.
If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is found there, suspect PCM programming error or faulty PCM.
To test the O2 sensors: Start the engine and let it reach its normal operating temperature. Let the engine idle (with the transmission in neutral or park). With the scanner connected to the vehicle’s diagnostic port, observe the oxygen sensor input data on the data stream. Limit the scope of the data stream to include only relevant data, and you will get a faster response.
If the oxygen sensors are functioning normally, the voltage on the pre-cat oxygen sensors will continuously cycle between 1 and 900 millivolts once the PCM enters closed-loop operation. The post-cat sensors will also cycle between 1 and 900 millivolts, but they will stabilize at a certain point and remain relatively stable compared to the pre-cat sensors. Oxygen sensors that are not functioning properly should be considered faulty if the engine is in good operating condition.
A blown O2 sensor fuse is not the cause of a stored P2246 code, but a reaction to some type of short circuit in the circuit.