M11 Series Engines – Air Compressor Will Not Maintain Adequate Air Pressure (Not Pumping Continuously)

Symptom Tree  t008

This is symptom tree t008
Cause Correction

Air system leaks

Block the vehicle wheels and check the air system for leaks with spring brakes applied and released. Check for leaks from the air compressor gaskets and the air system hoses, fittings, tanks, and valves. Refer to Procedure 012-019 and the OEM service manuals.


Air governor is malfunctioning or not set correctly

Check the air governor for correct operation. Refer to Procedure 012-017.


Air compressor intake or exhaust valve leaks air

Inspect the air compressor intake and exhaust valve assemblies. Refer to Procedures 012-103, 012-104, or 012-106.


Cover gasket is ruptured (Holset® SS models only)

Check the discharge line for blockage. Refer to Procedure 012-013. Check the cover gasket for flatness. Replace the cover gasket.

Last Modified:  05-Jan-2004