Technical Description of OBD-II Trouble Code
Barometric Pressure Sensor B
What does that signify?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles. It can affect various vehicles including Chevy, Mazda, Volvo, Acura, Honda, BMW, Isuzu, Mercedes Benz, Cadillac, Hyundai, Saab, Ford, GMC, etc. The repair steps may vary depending on the year, make, model, and powertrain configuration.
Most Engine Control Modules (ECMs) rely on multiple measurements to provide the engine with the optimal air to fuel ratio. The ideal air/fuel ratio is known as the “stoichiometric” mixture, which is 14.7 parts air to one part fuel. The ECM monitors various values such as air flow, coolant temperature, engine speed, load demand, atmospheric temperature, etc., to maintain the stoichiometric mixture. Some engine management systems prioritize intake and atmospheric pressures for optimizing the mixture.
In some cases, Barometric Air Pressure (BAP) sensors are used alongside Manifold Absolute Pressure (MAP) sensors. BAP sensors measure atmospheric pressure, which is crucial for determining fuel mixtures. Altitude plays a significant role in diagnosing BAPs, as symptoms may worsen or improve depending on the location, especially in mountainous areas.
When a letter is included in an OBD2 fault code’s description (such as “B” in this case), it often indicates a specific aspect of the system being addressed, such as different banks, sensors, circuits, connectors, etc. In this case, it helps determine which sensor is involved. Multiple barometric sensors are often used to ensure accurate readings and assist in fuel management. It also aids in identifying faults within the sensors or circuits. Consult your service manual for specific details regarding letter specifications for your vehicle.
P222A is set by the ECM when it detects a general or specific malfunction in the Barometric pressure (BAP) “B” sensor or its circuit(s).
A barometric pressure sensor:
What is the severity of this DTC?
The severity of this DTC is moderately high. It requires immediate attention to maintain efficient engine operation. If a fault can directly impact critical values like air/fuel ratios and is actively present, it is advisable not to operate the vehicle to prevent engine damage. However, if you have driven the vehicle since the fault occurred, there may not be immediate cause for concern. Nevertheless, if left unattended, this fault could potentially lead to expensive internal engine damage in the future.
What are some of the symptoms of the code?
Symptoms of a P222A trouble code may include:
What are some of the common causes of the code?
Possible causes for this P222A code include:
What are some P222A troubleshooting steps?
Basic Step #1
Locate the Barometric Air Pressure (BAP) sensor on your specific vehicle. The sensor’s location can vary significantly, so it is crucial to find the correct sensor. Inspect the BAP sensor for any physical damage, considering factors like high heat areas, engine vibrations, exposure to elements/road debris, etc.
Basic Step #2
Ensure that the connector on the sensor is properly seated to establish a good electrical connection. Vibrations, especially if the sensor is located on the engine, can cause loose connections or physical damage.
NOTE: Remember to disconnect the battery before disconnecting any sensors to avoid damaging electrical spikes. If you are uncomfortable or have limited electrical knowledge, it is recommended to have your vehicle towed/driven to a reputable repair facility.
Basic Step #3
Check for any obstructions that may be affecting the sensor. Obstructions can lead to false atmospheric pressure readings, which can impact engine performance in fuel management systems.
Basic Step #4
Using a multimeter, follow the manufacturer’s specific diagnostic procedures and desired electrical values for the barometric air pressure sensor. Disconnect the connector from the sensor to access the pins. Compare the readings with the specified range. Any values outside the range indicate a defective sensor, which should be replaced following proper procedures.
