How severe is this DTC?
An incorrect air/fuel ratio can result from insufficient fuel or excess air (vacuum). A P219B code should be classified as severe and corrected as soon as possible.
What are some of the symptoms of the code?
Symptoms of a P219B fault code may include:
- Reduced fuel efficiency
- Lack of overall 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
- A faulty mass airflow or manifold air pressure sensor
- Bad fuel pump or clogged fuel filter
What are the troubleshooting steps for P219B?
All misfire codes, throttle position sensor codes, manifold air pressure codes, and mass airflow sensor codes should be addressed before attempting to diagnose a P219B code. The engine must also be running properly and efficiently. If it is determined that there is a rich or lean condition (with the engine), this must be repaired as it may be the cause of the P219B being stored.
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information to accurately diagnose a P219B code.
You can save time by searching for Technical Service Bulletins (TSBs) that match the stored code, the 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 P219B 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.
If the engine is running correctly and the 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 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 running condition.
In most cases, you will fix this code by correcting a rich or lean running engine.