Technical Description of OBD-II Trouble Code
High Barometric Pressure Sensor A
What does that signify?
This is a generic diagnostic trouble code (DTC) for powertrain issues that typically applies to OBD-II vehicles. Affected vehicles may include but are not limited to Chevy, Mazda, Volvo, Acura, Honda, BMW, Isuzu, Mercedes Benz, Cadillac, Hyundai, Saab, Ford, GMC, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
Most Engine Control Modules (ECMs) rely on various measurements to accurately provide the engine with the optimal air to fuel ratio. The “optimal” air/fuel ratio is known as the “stoichiometric” mixture, which is 14.7 parts air to one part fuel. Some of the values that the ECM monitors to maintain the stoichiometric mixture include, but are not limited to: air flow, coolant temperature, engine speed, load demand, atmospheric temperature, etc. Some engine management systems prioritize intake and atmospheric pressures to optimize the mixture.
Additionally, these systems use fewer sensors to achieve similar results in terms of fuel management and efficiency. Barometric Air Pressure (BAP) sensors are typically used in conjunction with Manifold Absolute Pressure (MAP) sensors. BAPs measure atmospheric pressure, which is crucial for determining fuel mixtures. The ECM compares atmospheric pressures to intake manifold pressures in order to accurately adjust the fuel mixture based on the driver’s needs. Altitude plays a significant role in diagnosing BAPs, as symptoms may worsen or improve depending on the location, especially if frequent commuting through mountainous areas is involved.
When a letter is included in the description of an OBD2 fault code (such as “A” in this case), it is often used to specify something particular about the system being worked on, such as different banks, sensors, circuits, connectors, etc. In this case, it is likely used to determine which sensor is being addressed. Multiple barometric sensors are often used to ensure accurate readings and to assist in fuel management. Additionally, they help identify faults within the sensors or circuits. For specific details on letter specifications for your particular vehicle, refer to your service manual.
P2229 is set by the ECM when it detects a high electrical value/reading in the Barometric pressure (BAP) “A” 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 is important to address this issue promptly in order to maintain efficient engine operation. If a fault can directly impact critical values such as air/fuel ratios and is actively present, it is advisable not to operate the vehicle to prevent any potential engine damage. However, if you have driven the vehicle since the fault became active, there may not be immediate cause for concern. It is crucial to address this fault to avoid expensive internal engine damage in the future.
What are some of the symptoms of the code?
Symptoms of a P2229 trouble code may include:
What are some of the common causes of the code?
Causes for this P2229 code may include:
What are some P2229 troubleshooting steps?
Basic Step #1
Locate the Barometric Air Pressure (BAP) sensor on your specific vehicle. The location of these sensors can vary significantly, so it is important to prioritize finding the correct sensor. Once located, inspect the BAP sensor for any physical damage. Consider the sensor’s surroundings (e.g. high heat areas, engine vibrations, exposure to elements/road debris, etc.) as possible factors contributing to issues.
Basic Step #2
Ensure that the connector on the sensor itself is properly seated to establish a good electrical connection. If the sensor is located on the engine, it may be subject to vibrations that could loosen connections or cause physical damage.
NOTE: Remember to disconnect the battery before disconnecting any sensors to avoid causing damaging electrical spikes. If you are uncomfortable with this step or have limited knowledge of electrical systems, 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 are crucial for optimal engine performance in fuel management systems.
Basic Step #4
Using a multimeter and the desired electrical values for the barometric air pressure sensor, disconnect the connector from the sensor to access the pins. Follow manufacturer-specific diagnostic procedures with the desired values and compare them. Any values outside the specified range indicate a defective sensor. Replace the sensor following proper removal and installation procedures.
