How severe is this DTC?
An incorrect air/fuel ratio can result from insufficient fuel or excess air (vacuum). A P219A code should be classified as severe and corrected as quickly as possible.
What are some symptoms of the code?
Symptoms of a P219A fault code may include:
- Reduced fuel efficiency
- General lack of 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:
- Engine vacuum leak (large)
- Faulty oxygen sensor(s)
- Burned, chafed, broken, or disconnected wiring and/or connectors
- Engine exhaust leaks
- Faulty mass airflow or manifold air pressure sensor
- Bad fuel pump or clogged fuel filter
What are the troubleshooting steps for P219A?
All misfire codes, throttle position sensor codes, manifold air pressure codes, and mass airflow sensor codes should be addressed before attempting to diagnose a P219A code. The engine must also be running properly and efficiently. If it’s determined that there is a rich or lean condition (with the engine), this must be repaired as it could be the cause of the P219A being stored.
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P219A code.
You can save time by looking for Technical Service Bulletins (TSBs) that match the recorded code, vehicle (year, make, model, and engine), and the symptoms presented. 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 actually be more difficult to diagnose if the PCM enters readiness mode at this point, as the code is intermittent. The condition that caused the P219A 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 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.
If the engine is running smoothly and the P219A/P219B code continues to reset, 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’ll 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 running condition.
In most cases, you will fix this code by correcting a rich or lean running engine.