I haven't dealt with a monitor not running before, but have dealt with other issues with these systems. Most common failures seem to be diverter valves and pumps.

Check to make sure your vacuum solenoid is not allowing partial vacuum when disabled. It could lead to excess air getting to the O2 sensors. Check fuel trims while blocking off motor outlet.

Outside of that quick check, AllData has a list of variables that will disable the AIR system: The AIR system is disabled under the following conditions:

^ The PCM recognizes a problem and sets a diagnostic trouble code.

^ The AIR pump has been ON for 240 seconds.

^ The engine speed is more than 2,825 RPM.

^ The Manifold Absolute Pressure (MAP) is more than 96 kPa with Vehicle Speed Sensor (VSS) over 96.5 km/h (60 mph).

^ The Manifold Absolute Pressure (MAP) is less than 20 kPa.

^ Warm up 3-way catalytic converters over temperature detected.

^ The short and long term fuel trim are not in their normal ranges.

^ Power enrichment is detected.

Most of these variables can be checked via a quick lookover of scan data PIDS. Of most importance is to make sure your temp and pressure sensors are accurate.

Lastly, I have seen monitors not run because of mismatched VINs inside the PCM or other modules. Make sure to check this as well.

Nathan Haynes
Technician
Columbia Auto Care
Columbia, Maryland, USA