M11 Series Engines – Air Compressor Will Not Pump Air

Symptom Tree  t009

This is symptom tree t009
Cause Correction

Air governor is malfunctioning or not set correctly

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


Unloader valve is malfunctioning

Check the unloader valve and unloader body seal. Refer to Procedure 012-013.


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.


Air compressor is excessively worn or internally damaged

Replace or rebuild the air compressor. Refer to Procedure 012-014. Replace the desiccant element on the Turbo/CR 2000 air dryer (if equipped). Refer to the manufacturer’s instructions.


Cover gasket is ruptured (Holset® SS models only)

Check the discharge line for blockage. Refer to Procedures 012-003, 012-103, 012-104, and 012-106. Check the cover gasket for flatness. Replace the cover gasket.

Last Modified:  30-Jan-2004