How severe is this DTC?
An open O2 sensor reference voltage circuit can lead to decreased fuel efficiency and reduced engine performance. A P2247 code should be classified as severe and rectified as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P2247 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, rubbed, broken, or disconnected wiring and/or connectors
What are the troubleshooting steps for P2247?
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P2247 code.
You can save time by searching for Technical Service Bulletins (TSBs) that match the recorded code, the vehicle (year, make, model, and engine), and the 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 P2247 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 diagrams, component location diagrams, wiring diagrams, and diagnostic flowcharts (related to the code and the 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 a 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 recorded P2247 code, but a reaction to some type of short circuit in the circuit