P2229: The LIN barometric-pressure value exceeds its upper limit

P2229 reports an excessively high BARO pressure value in the reviewed GM LIN-MAF application. The code's circuit-high title should not be interpreted automatically as an exposed analog wire shorted to battery voltage.

What the controller receives

In this implementation the barometric transducer's pressure-dependent voltage is converted into a value that the MAF sensor transmits over LIN. Monitoring begins only after that communication is established. The ECM judges reported pressure above 110 kPa to be outside the documented range.

Thus the important initial distinction is a valid message containing an implausible pressure versus an absent or invalid communication path. This row concerns the former monitoring arrangement; it does not provide a general communications diagnosis.

Why one reading is insufficient

The decision requires 160 failed observations out of 200 at 25-millisecond sampling. Preserve the duration and stability of the high value, along with communication status, when trying to reproduce the event.

Use the correct absolute-pressure parameter when comparing scan data with an independent ambient reference. A different pressure convention or a substituted manifold-pressure reading can make a comparison meaningless. These comparisons are diagnostic reasoning, not proof that a particular component has failed.

Verification should show a plausible LIN BARO value throughout an enabled monitor evaluation. The source lists Type A, one-trip behavior but gives no universal sensor-output voltage, part location or repair prescription. Its 110-kPa limit applies to this documented calibration only.

Source and applicability

The documented system and calibration must be confirmed for the vehicle before using these limits. GM diagnostic table, PDF page 617.