DEF LIGHT ON AGAIN?

One of the most frequent questions we get asked over the phone at Big Shop is something along the lines of, “My DEF light is on and blinking. Was does that mean?” So, in this week’s blog we’re going to breakdown what the DEF Light could be signifying, and what your next steps should be.

 

SCENARIO ONE: YOUR DEF LIGHT IS ON.

If your DEF indicator light in on, and is staying on (aka not blinking), it is attempting to tell you that your DEF level is below the established threshold. Your solution is simple, all you have to do is refill your DEF tank. Just fill it up, the light will go off, and you’ll be on your way.

SCENARIO TWO: YOUR DEF LIGHT IS FLASHING/BLINKING.

A flashing/blinking DEF indicator light means that your DEF level is critically low. That means drop whatever you’re doing and refill it. If you continue on ignoring that indication, the consequences could be dire. So, refill the DEF tank as soon as possible.

SCENARIO THREE: YOUR DEF LIGHT IS FLASHING/BLINKING, AND THE CHECK ENGINE LIGHT IS ON.

A flashing DEF Light combined with a Check Engine Light indicates that the DEF level is critically low and you will derate. Normal engine power will be restored after refilling the DEF tank. Essentially, you ignored the DEF light when it was blinking, and now you have to refill the tank before you can do much else.

SCENARIO FOUR: YOUR STOP ENGINE LIGHT IS ON WITH FLASHING DEF & CHECK ENGINE LIGHT.

If the engine has been shut down or has idled for one hour after the DEF tank has been run dry, the Stop Engine Light will also be lit along with the flashing DEF Lamp and Check Engine Light. Engine power will continue to be reduced automatically. The vehicle will also be limited to a speed of 5 miles per hour. Normal engine power and vehicle speed will be restored after refilling the DEF tank.
Clearly, that DEF light is a very important indicator. If you have any more questions about your DEF light, if you think it’s lit up in error, or if you have any other concerns regarding your truck; give us a call at Big Shop Diesel. We’ve got the parts and expertise, combined with old fashioned customer service, to keep you up and running. You can reach us at 972-590-8565.