Manifold Absolute Pressure/BARometric Pressure Correlation

The engine's computer is seeing a big difference between the pressure readings of the manifold and the atmosphere, which usually means there's a problem with the sensors or air intake system.

The Engine Control Module (ECM) compares the readings from the manifold pressure sensor and the barometric pressure sensor. If the difference exceeds a specific limit (typically around 3-5 kPa), the code is triggered.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Start with a visual inspection of the MAP and BARO sensor wiring and connectors. Look for any signs of damage or loose connections. If damaged, repair or replace as necessary. Decision point: Are wiring and connectors good? (Yes/No)
2. 22. Use a scan tool to read live data of the MAP and BARO sensor. Compare the values and check for any discrepancies. Is the MAP reading significantly higher or lower than the BARO reading when the engine is running? (Yes/No)
3. 33. Perform a vacuum leak test in the intake system. Use smoke or carb cleaner method. Are there any vacuum leaks present? (Yes/No)
4. 44. If all sensors and wiring are good with no vacuum leaks, test the MAP and BARO sensors' voltage signals using a multimeter. Expected voltage should be around 0.5V at idle and proportional to the pressure. Do the signals match expected values? (Yes/No)
5. 55. If issues persist, consider testing or replacing the ECM.

• Faulty manifold absolute pressure (MAP) sensor
• Faulty barometric pressure (BARO) sensor
• Vacuum leaks in the intake system
• Damaged wiring or connectors for the MAP or BARO sensor
• Failed ECM

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