ISBe/ISB Series Engines – Intake Manifold Pressure (Boost) is Below Normal

Air intake or exhaust leaks

Check for loose or damaged piping connections and missing pipe plugs. Check the turbocharger and exhaust manifold mounting. Refer to Section 3.

Air intake system restriction is above specification

Check the air intake system for restriction. Clean or replace the air filter and inlet piping as necessary. Refer to Section 4 and Section A.

Charge air cooler is restricted or leaking

Inspect the charge air cooler for air restrictions or leaks. Refer to Section 4.

Electronic fault codes are active

For instructions on how to read active fault codes, refer to Diagnostic Fault Codes in Section 1. If fault codes are active, contact a Cummins Authorized Repair Facility.

Intake manifold pressure sensor is malfunctioning

Check the intake manifold pressure sensor. Refer to a Cummins Authorized Repair Facility.

Engine power output is low

Refer to the Engine Power Output Lowsymptom tree.

Engine is operating above recommended altitude

Engine power decreases above recommended altitude. Refer to the Engine Power Output Lowsymptom tree.