P2229 is a generic OBD-II powertrain code standardized as “Barometric Pressure Sensor Circuit High.” It applies to vehicles equipped with a dedicated barometric pressure sensor or a manifold absolute pressure sensor that also calculates barometric pressure.
This code indicates the control module detected a voltage signal from the barometric pressure sensor circuit that is consistently above the expected maximum range. It does not automatically prove the sensor itself has failed.
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Key Takeaways
- P2229 indicates a high voltage condition detected in the barometric pressure (BARO) sensor signal circuit.
- Possible causes include a short to voltage in the wiring, a corroded connector, or a failed BARO or MAP sensor.
- On many applications, the BARO sensor is integrated directly into the manifold absolute pressure (MAP) sensor or the powertrain control module (PCM).
- Diagnosis requires comparing live BARO data to known atmospheric pressure and testing the sensor circuit for electrical faults.
P2229 Code Description and Implications
P2229 is a generic OBD-II powertrain code standardized by SAE as “Barometric Pressure Sensor Circuit High.”
The powertrain control module (PCM) uses barometric pressure data to adjust fuel delivery, ignition timing, and transmission shift points based on altitude and atmospheric density.
On many applications, the barometric pressure (BARO) sensor is integrated directly into the manifold absolute pressure (MAP) sensor. On others, it is a standalone sensor or built directly into the PCM circuit board.
When the PCM detects that the voltage signal from the BARO sensor circuit remains consistently above the calibrated maximum threshold, it stores P2229.
This code identifies a detected high-voltage electrical condition; it does not automatically prove that the sensor itself has failed internally.
Common Causes of the P2229 Code
Because P2229 specifically identifies a high-voltage condition in the circuit, the root cause usually involves a short to voltage or an abnormal resistance in the signal path.
Possible causes include a short to the 5-volt reference circuit or battery voltage in the wiring harness connecting the BARO or MAP sensor to the PCM.
A loose, disconnected, or corroded electrical connector at the sensor or the PCM can also interrupt the proper ground or signal return, causing the voltage to float high.
A failed internal component within the BARO sensor, MAP sensor, or a PCM internal fault may trigger this code.
In some applications, a damaged or pinched wiring harness near the firewall or sensor mounting location can cause an intermittent short.
Symptoms Associated With P2229
The most consistent symptom is an illuminated Check Engine Light.
Because the PCM relies on barometric pressure for altitude compensation, the vehicle may exhibit hesitation, stumbling, or poor acceleration, particularly at higher elevations.
The transmission may exhibit altered or harsh shift points, as some modules use atmospheric pressure data to adjust line pressure.
In some applications, the driver may notice no drivability symptoms other than the warning light, especially if the PCM substitutes a default barometric value.
MIL behavior varies by application. Some vehicles may illuminate the Check Engine Light immediately, while others may require multiple drive cycles.
Diagnosing the P2229 Trouble Code
Diagnosis must begin by confirming the exact factory definition and wiring diagram for the specific make, model, and engine.
Retrieve the code and record any freeze-frame data or related error codes using a scan tool capable of displaying live data.
Monitor the live BARO sensor data with the Key On, Engine Off (KOEO). Compare the BARO reading to the MAP sensor reading; at KOEO, both should read nearly identically to the actual local atmospheric pressure.
If the BARO reading is pegged at the maximum limit, check the signal circuit for a short to the 5-volt reference or battery voltage.
Visually inspect the wiring harness and electrical connectors at the sensor and the PCM for physical damage, chafing, or corrosion.
If the wiring and connectors test within specifications, further diagnosis of the sensor or PCM driver circuit may be required.
Repairing the P2229 Issue
Repairs must follow the confirmed root cause identified during electrical testing.
If wiring damage or a short to voltage is found, repair or replace the affected harness section and clear the code.
If the electrical connector is corroded or damaged, repair the terminals or replace the connector pigtail.
If the BARO or MAP sensor fails the manufacturer’s electrical and functional tests, replace the sensor with a component meeting the correct vehicle specification.
If the BARO sensor is integrated into the PCM and all external wiring tests correctly, follow the applicable PCM replacement and programming procedure.
Always clear the codes and perform a test drive to verify the repair and ensure the monitor completes successfully.
Cost Considerations for P2229 Repairs
Repair costs for P2229 vary based on the underlying fault, vehicle accessibility, and local labor rates.
Wiring repairs or connector replacements are typically the least expensive fixes, requiring only minor labor and basic materials.
Replacing a standalone BARO or combined MAP/BARO sensor involves moderate parts costs and minimal labor time.
If the repair requires replacing and programming the PCM because the BARO sensor is internally mounted, parts and diagnostic costs will be higher.
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Prevention Strategies for Future Occurrences
Keeping electrical connectors clean and ensuring wiring harnesses near sharp metal edges or hot exhaust components are securely routed can help prevent chafing and short circuits.
Inspecting exposed wiring and sensor connectors during routine service can help identify developing damage or moisture intrusion before it causes an open or shorted circuit.
Ensuring that aftermarket accessories are not spliced into the factory sensor reference voltage circuits helps prevent accidental shorts to voltage.
Troubleshooting Tips and Best Practices
Do not assume a P2229 code automatically requires replacing the sensor; a shorted wire or a bad ground will produce the exact same high-voltage electrical signature.
Do not use consumer weather-app sea-level pressure to verify the BARO sensor; use the actual uncorrected local atmospheric pressure or compare it directly to the MAP sensor at KOEO.
Check for applicable technical service bulletins, as some manufacturers release updated sensor part numbers, revised wiring harnesses, or PCM software recalibrations to address premature circuit failures.
Verify that the correct sensor is installed, as using an incorrect MAP/BARO sensor can output the wrong voltage scale and trigger high or low circuit codes.
More OBD-II Codes
| P2228 | P2227 | P2200 | P2099 |
| P2098 | P2097 | P2237 | P2238 |
| P2261 | P2262 | P2263 | P2401 |
| P0107 | P0108 | P0101 | P0100 |
| P0171 | P0174 | P0172 | P0170 |
| P0131 | P0132 | P0133 | P0137 |
Frequently Asked Questions
Is P2229 a generic or manufacturer-specific code?
Yes. P2229 is a generic OBD-II code standardized by SAE. It carries the same basic definition across all manufacturers, though exact diagnostic procedures and sensor locations vary by application.
Can a P2229 code affect my vehicle’s transmission shifting?
Yes. Many control modules use barometric pressure data to adjust transmission line pressure and shift points for altitude compensation. A faulty BARO signal can cause harsh or delayed shifts.
Will P2229 clear itself if the weather changes?
Not automatically. If a short to voltage or failed sensor triggered the code, the physical electrical fault remains. The monitor may pass under certain conditions, but the stored code requires a scan tool to clear.
Is it safe to drive with the P2229 code active?
The vehicle is usually safe to drive to a repair facility. However, you may experience reduced engine performance, hesitation, or altered transmission shifting, especially at higher elevations.
Does P2229 mean I need to replace the PCM?
No. While some vehicles integrate the BARO sensor inside the PCM, wiring shorts, corroded connectors, or a failed external MAP/BARO sensor are also possible causes. Never replace the PCM without confirmed diagnosis.
What Should You Do About the P2229 Code?
Confirm the exact factory definition and wiring diagram for your specific vehicle application.
Follow the applicable manufacturer diagnostic procedure to test the barometric pressure sensor circuit, wiring harness, and module inputs.
Repair or replace the confirmed failed component, then retest the system to ensure the code does not return.
