P04E3: PCV hose pressure output above its electrical ceiling

The cited GM P04E3 monitor detects short-to-power behavior in the crankcase ventilation pressure signal circuit. Its failure boundary is at or above 95.5 percent of the five-volt range. The document maps that output to 5.69 kPa for the described pressure sensor.

Pressure conversion does not validate the signal

The transducer measures gauge pressure relative to atmosphere. An electrically excessive output can therefore create an apparent pressure reading without proving the crankcase actually reached that pressure. Establish signal integrity before turning the displayed value into a mechanical PCV diagnosis.

This monitor counts 1,280 failing observations out of 1,600 at a 3.125-millisecond sampling interval and uses Type B reporting. A later normal reading cannot exclude an earlier sustained high event recorded by those counters.

Verification should target the high circuit

Save the voltage or normalized output, derived pressure and related fault record. Identify the actual circuit using the correct engine documentation, then apply its approved short-high diagnostic procedure. The source does not distinguish the sensor, harness or controller as the cause from P04E3 alone.

After correction, confirm the enabled circuit-high monitor completes without repeated excessive output. A hose that appears connected or a normal engine idle does not test the electrical ceiling. Once pressure data are valid, any separate PCV performance concern can be evaluated with its own documented criteria.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 313. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.