Fuel and air

P2225 — Barometric Pressure Sensor Circuit Malfunction

Severity: medium Drive with care, to a shop

What P2225 means

The engine control module found a problem in the barometric pressure sensor circuit: the signal is out of range or does not agree with other sensors. The ECM uses ambient pressure to adjust fueling, boost and ignition timing, especially when altitude changes. The sensor may be built into the ECM or mounted separately, for example in the intake.

Symptoms

  • Check Engine light on
  • Rough idle, especially when altitude changes
  • Loss of power or sluggish acceleration
  • Higher fuel consumption
  • Hard starting or hesitation when climbing
  • Torque limitation on some vehicles

Possible causes

  1. Failed external BARO sensor
  2. Failed sensor inside the ECM
  3. Open or shorted sensor wiring
  4. Corroded or loose connector terminals
  5. Missing 5 V reference or ground at the sensor
  6. Faulty MAP or boost pressure sensor that the BARO signal is compared against

How to diagnose

  1. Scan for codes and freeze-frame data, and look for related MAP, boost or pressure sensor codes
  2. With key on and engine off, compare BARO reading with actual ambient pressure; it should be close to the MAP reading
  3. Inspect the sensor connector and harness for corrosion, moisture and damage
  4. Use a multimeter to check 5 V reference, ground and signal wire
  5. Test the signal wire for opens and shorts to power or ground
  6. Check the MAP sensor and any air or vacuum lines if readings disagree
  7. If the sensor is inside the ECM, check ECM power and grounds, then look for service bulletins and software updates

Common fixes

  • Replace the external barometric pressure sensor
  • Repair wiring or replace a damaged connector
  • Clean terminals and eliminate moisture intrusion
  • Replace or reflash the ECM if the internal sensor failed
  • Update ECM software per the manufacturer bulletin, then clear the code and retest

Questions and answers

What does P2225 mean?

It indicates a fault in the barometric pressure sensor circuit. The ECM receives an incorrect or implausible ambient pressure signal and cannot correct fueling accurately.

Can I drive with P2225?

For a short time, yes, but power and fuel economy may suffer and some vehicles limit torque. Don't put off diagnosis.

Why is this code tied to altitude?

Air gets thinner as you climb, and the ECM uses the BARO signal to trim fuel and boost accordingly. A bad signal breaks that correction.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.