Tier 4 Final DEF Lamps

Cummins Tier 4 Final off-highway engines with >751 hp require little to no operator interaction. Other than refueling, the only regular action you will need to perform is refilling the Diesel Exhaust Fluid (DEF) tank periodically. All of Cummins Tier 4 Final engines with >751 hp require Diesel Exhaust Fluid (DEF) for their aftertreatment exhaust systems and have DEF Lamps and Gauges that indicate when the DEF tank needs to be filled.

DEF Lamp OnDEF Lamp
Illuminates when DEF level is low, and flashes when the DEF falls below a very low level. Operator should refill the DEF tank with DEF.

check_engine_and_def_lampAmber Warning Lamp
Illuminates when DEF level is critically low. Engine power has been significantly reduced. Operator should refill the DEF tank with DEF immediately.


red stop lampRed Stop Lamp
Illuminates when continued operation could result in damage to the exhaust system. Shut down the engine as soon as it is safe to do so, and call for service, or risk damage to the exhaust system.