What does the code p21dd on a Duramax mean?

The code p21dd is Reductant heater1 circuit low. The heating elements in your DEF have done faulty. This is a common problemYou can do the repairs yourself if you like.

Why is my 2013 LML throwing a p21dd code?

My 2013 is at 53,000 miles,3,000 past emissions warranty. We’ve started getting colder mornings and its started throwing a P21DD code. Based on a search. It appears to be a DEF tank heater issue, but I can’t find much info about it. Is the tank heater hard to replace? Where can I find the part number? Any help is appreciated.

What does code p21dd mean on Def heater?

The latest part to fail was the reductant tank heater (DEF Heater). Upon cold start the check engine light came on with code P21DD. After a little reading I learned that this can result in “Limp Mode”. I was in the middle of nowhere in Northern Wyoming. Not cool! I drove down to Denver and replaced it that week.

How long is the p21dd covered under warranty?

Drained tank, removed tank. Replaced reservoir. Installed and filled tank. Used scan tool to command all heaters on-heater #1 is operating in spec again. Cleared code. Just wondering is this the “special warranty” I saw on the paperwork when I bought my truck used? I have about 76000kms on it now and no bumper to bumper left.

What is the p21dd code on my Chevy Duramax?

I have reset it. The check engine light comes on when I accelerate aggressively. It show two codes P21DD and P21DD with small PD above the last D. I am able to reset the code each time. Mechanic’s Assistant:What is the model of your ’15 Chevy?

What does p21dd mean on a diesel truck?

They said P21DD is, as we know, an issue with the reduction tank heater. Spec says it should be from 5 to 7 amps, mine is at 3.46 max. They quoted me $679 to replace, I believe the heater plus tank. They say the truck will eventually go in limp mode…I would rather put the $679 towards deleting this system!