Cruze Diesel DEF Reservoir Heater Failures

One of the common failure items on a Gen1 Chevy Cruze diesel is the DEF tank reservoir heater.

Diesel exhaust fluid begins to freeze at 12 degree fahrenheit. Manufacturers use a heater in the DEF tank to thaw the fluid and allow it to enter the exhaust system, however, this can fail over time. Normally a DEF heater failure will cause the CEL to illuminate and a P21DD code to be signaled, but in some cases the CEL will not illuminate. When the CEL does not illuminate, the Cruze will display a message stating “DEF quality poor”.  Often times the dealer will drain and refill the DEF from the reservoir claiming bad DEF is causing the issue, but that is rarely the case. Chevy has extended the warranty on the reservoir heater to 10 years/120k miles. The warranty covers the replacement part and labor for the heater install. The part has been redesigned by Chevy to not fail prematurely. We haven’t seen any reports of failures after the heaters had been replaced with newer versions.  Once the heater is replaced the vehicle will need to be driven up to 100 miles for the code to clear from the system. If your vehicle is out of the extended warranty period the replacement is a simple but messy job that can be accessed from the trunk. If you attempt this job and have any questions, don’t hesitate to give us a call. We are always happy to help!

  1. Is there some sort of warranty code # to reference for this issue?


    1. I have this issue, the dealer is fixing it, ideally dont want to pay anything. The dealer said its not covered under my car warranty which is true but this is separate?


  2. JUst happened twice this year, JAnuary, February 2018 on my 2016 Chevrolet Colorado 2.8 litre diesel turbo. Covered by warranty, but it is going to be covered for 10 years, 120k miles?

    I very well hope so, $1500 + taxes


  3. We have a 2014 Chevy Cruze. Chevrolet replaced the DEF Reservoir in June, 2016 at no charge, and then did it again yesterday at no charge. (We had a pretty cold winter here in North Texas this year.)

    Do you think the latest version will last longer, or is two years an expected lifespan? This is the only time I’ve ever had a tech problem like this hold me hostage to get it fixed. Without this component working correctly, we would eventually not be able to drive the car at all.


  4. My 2014 diesel Cruze with 107K just had the dreaded limp mode start. Code P21DD. First issue with my Cruze, outside of the crappy radio – negative battery terminal garbage.


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