Category: Excessive Exhaust Smoke (Black or Gray)
- Series 50 – Section 21.6 Defective Turbocharger
- Series 50 – Section 21.4 Faulty Exhaust System
- Series 50 – Section 21.5 Faulty Fuel Injector
- Series 50 – Section 21.1 Improper Grade of Fuel Oil
- Series 50 – Section 21.2 Restricted Air Cleaner Element
- Series 50 – Section 21.3 Restricted or Cracked Charge Air Cooler