GMC Sierra 2015 5.3L Engine P0641 and P2228 Codes: Causes, Symptoms, and Troubleshooting Guide

The P2228 code typically points to issues with the Barometric Air Pressure (BAP) sensor. Possible causes include: a defective or damaged BAP sensor, faulty electrical connectors, wiring problems such as open circuits, shorts, or corrosion, internal or mechanical electrical shorts, loose connections, heat damage, or mechanical malfunctions affecting readings. The Engine Control Module (ECM) may also be at fault. Recommended troubleshooting steps: - Check for voltage drops in the BAP sensor circuit using a multimeter. - Inspect wiring harnesses and connectors for signs of wear or corrosion. - Verify that the BAP sensor is properly grounded and connected. More details available: https://www.p2228.com

I'm having trouble locating the BAP sensor on my 2015 GMC Sierra. Does anyone know where it's physically located in this model year and engine configuration? Is it accessible or integrated into another component?

Note that the Barometric Air Pressure (BAP) sensor is often integrated with the Multi-Function Intake Air Sensor, which is built into the MAF (Mass Air Flow) sensor. In many 2015 GMC Sierra 5.3L engines, this integration means the BAP function relies on the same wiring and power circuit as the MAF.

I've updated my situation: the truck runs smoothly under normal conditions, but when I press the throttle halfway, there's a noticeable lag in acceleration. The P0641 code flashes intermittently during this action. Once I release the pedal, everything returns to normal. However, I can only accelerate gently—any aggressive input causes hesitation. Interestingly, when I shift into neutral or park and rev the engine manually, it responds normally even with the P0641 code present.

The P2228 issue may stem from a faulty BAP sensor or an integrated multifunction intake air sensor within the MAF. Since the BAP sensor depends on a stable 5V reference voltage, any malfunction in that circuit can trigger both P2228 and P0641. I recommend checking for short circuits among multiple sensors sharing the same 5V reference line. The ECM may default to backup strategies if one sensor fails. Do you have a digital multimeter? If so, testing voltage at the MAF sensor terminals could help identify issues. I can share wiring diagrams via email if needed.

It's important to investigate both P2228 and P0641 thoroughly. The P0641 code indicates an incorrect 5V reference voltage. To troubleshoot: - Disconnect the MAF sensor (8-pin connector) and observe if engine performance improves. - Use a multimeter to check for proper 5V reference voltage at the BAP/MAP sensor wiring harness. Multiple sensors may share the same 5V reference circuit—check for any shorted or faulty sensors pulling down the voltage. For detailed schematics, consider using ALLDATA.com or BBBind.com (free diagrams available), though coverage varies by model year. Clarify whether you're seeing a flashing check engine light or intermittent code cycling. Also, please share fuel trims, MAF/MAP readings, and freeze frame data from your scan tool for deeper diagnosis.

In the 2015 GMC Sierra 5.3L engine, the barometric pressure (BAP) sensor is not a standalone unit—it's integrated into the multifunction intake air sensor located within the MAF housing (8-pin connector). This combined sensor provides both airflow and barometric data. The system has multiple sensors sharing one 5V reference circuit. A shorted or faulty sensor could pull down the voltage, triggering P0641 (incorrect 5V reference) and P2228 (abnormal BAP readings). I recommend disconnecting the MAF sensor to see if engine behavior improves—this will allow the PCM to use a default strategy. If the issue resolves temporarily, it confirms a sensor-related fault. A digital multimeter is essential for voltage testing. I’ve sent wiring diagrams via email—please confirm receipt and let me know if you can read them.

The barometric pressure (BARO) sensor is integrated into the multifunction intake air sensor and detects changes in altitude and atmospheric conditions. This data helps the Engine Control Module (ECM) calculate fuel delivery accurately. The BARO sensor sends a voltage signal to the ECM, which monitors it for values outside normal ranges. A malfunction can lead to incorrect fuel mixtures, idle instability, or stalling.

I've sent detailed wiring diagrams for your 2015 GMC Sierra 5.3L model. Please confirm if you received them and whether they are readable and helpful for diagnosing the sensor circuits.

In most cases, the BAP function is handled by the MAF-integrated multifunction sensor, not a separate thermistor. It's unlikely that a standalone thermistor would be directly involved in barometric pressure sensing on this model.