Barometric Pressure Sensor "A" Circuit High
The barometric pressure sensor is reporting a voltage signal that is higher than the ECM's expected range. This sensor helps the engine computer adjust fuel mixture based on atmospheric pressure and altitude, so an out-of-range reading causes improper fuel trim and performance issues.
What You Might Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation during acceleration
- Difficulty starting in cold weather
- Performance issues that worsen at high altitudes
Most Common Causes
- 1
Faulty barometric pressure sensor
The sensor itself has failed and is sending an incorrect high voltage signal to the ECM. This is the most common cause of P2229.
- 2
Corroded or damaged sensor connector
Corrosion, moisture, or loose connections at the sensor connector can cause intermittent or consistently high voltage readings.
- 3
Wiring harness damage or short circuit
Damaged wiring between the sensor and ECM, or a short to voltage in the circuit, can cause the high voltage signal.
- 4
ECM electrical malfunction
Rarely, the ECM itself may have a circuit fault causing it to misinterpret normal sensor signals as high voltage readings.
How to Diagnose It
- 1
Check Faulty barometric pressure sensor — The sensor itself has failed and is sending an incorrect high voltage signal to the ECM. This is the most common cause of P2229.
- 2
Check Corroded or damaged sensor connector — Corrosion, moisture, or loose connections at the sensor connector can cause intermittent or consistently high voltage readings.
- 3
Check Wiring harness damage or short circuit — Damaged wiring between the sensor and ECM, or a short to voltage in the circuit, can cause the high voltage signal.
- 4
Check ECM electrical malfunction — Rarely, the ECM itself may have a circuit fault causing it to misinterpret normal sensor signals as high voltage readings.
How to Fix It
- 1
Replace barometric pressure sensor
Remove the faulty sensor from its mounting location (typically near the intake manifold or on the firewall) and install a new OEM or quality replacement sensor. Ensure proper connector seating and apply dielectric grease to prevent future corrosion.
- 2
Inspect and clean sensor connector
Disconnect the sensor connector and visually inspect for corrosion, moisture, or bent pins. Clean with electrical contact cleaner and ensure the connector is fully seated. Retest after reconnection.
- 3
Check wiring harness and repair damage
Inspect the wiring harness from the sensor to the ECM for cuts, pinches, or corrosion. Repair any damaged wiring with appropriate automotive wire and connectors, or replace the entire harness if extensively damaged.
- 4
Perform ECM diagnostics and reprogramming
If sensor and wiring tests pass, use advanced diagnostics to check ECM function and perform any necessary reflashing or replacement. This step requires specialized diagnostic equipment and should be done at a professional shop.
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