P2228: LIN-reported barometric pressure is below the permitted range

P2228 is a low barometric-pressure value in the reviewed GM implementation using a LIN-connected mass-airflow sensor. Although the dictionary calls it a circuit-low fault, this monitor evaluates a pressure value transmitted digitally to the engine controller.

Follow the actual signal path

The BARO transducer produces a pressure-dependent voltage inside the sensing arrangement. The MAF sensor then sends the resulting barometric-pressure value to the ECM over LIN. The diagnostic requires communication with that MAF device to be established.

Its failure criterion is reported BARO below 50 kPa. This is an absolute-pressure threshold, not a specified external signal voltage. Applying a generic analog BARO voltage test without confirming this architecture would investigate a different interface.

Persistence and plausibility

The controller requires 160 failures in 200 samples, taking a sample every 25 milliseconds. A transient displayed value and a sustained low value over the decision window carry different diagnostic weight.

First establish that the value being examined is the LIN-reported BARO parameter and that communication is functioning. Then compare its plausibility with appropriately obtained ambient-pressure evidence and the applicable sensor procedure. A low transmitted value does not identify whether the sensing element, associated electronics or another circuit condition is responsible.

After a repair, a meaningful check confirms plausible pressure reporting while the diagnostic is enabled and completion without recurrence. The table lists Type A, one-trip behavior, but does not establish model applicability, a connector pin or a mandatory MAF replacement.

Source and applicability

The documented system and calibration must be confirmed for the vehicle before using these limits. GM diagnostic table, PDF page 616.