P2229Powertrain
Powertrain · SAE
Barometric Pressure Sensor — Signal High
Meaning
The barometric pressure sensor (BARO) signal exceeds the maximum permitted threshold. The ECU interprets the voltage as too high, indicating a short to supply voltage, a failed sensor, or a pressure reading that is not plausible for the operating conditions.
Common causes
- Short circuit of the signal wire to supply voltage (5 V or 12 V)
- Internally failed BARO sensor (output stuck high)
- Connector with internally shorted pin
- Faulty ECU if BARO sensor is integrated (high reading from internal component)
- Electrical interference on the signal wire
Symptoms
- Check engine light on
- Barometric pressure value fixed at maximum on scan tool
- ECU calculates excessively high air density (as if vehicle were below sea level or air-overcharged)
- Air/fuel mixture too lean with risk of detonation
- Possible performance loss and engine damage from irregular combustion
Severity
Moderate to high: a high BARO signal causes the ECU to lean out the mixture; under high load this can cause knocking and engine damage.
What to do
- Measure BARO sensor output voltage; if above 4.5 V, investigate the short to supply
- Check sensor wiring with multimeter for shorts to the 5 V line
- Inspect connector for shorted pins or contamination
- If sensor is external, replace after verifying wiring
- If sensor is integrated in the ECU, consider ECU replacement