Diesel Tuner's Blog

Differences Between 49 and 50 State Tuning

Posted by Ben Lawson on Jan 17, 2023 8:10:00 AM

If you've ever been in search of emissions in tact tuning for your diesel truck you've probably come across the 49 state and or 50 state tuning label. While it may only seem like the difference between one state. How much of a difference can one state make? The answer may surprise you. This article will try to answer the top five most common questions regarding 50 state tuning. 

Cummins 50 State Email Graphic-1200.583

1. What is the difference between 49 and 50 state tuning?
2. Will I only need 50 state tuning if I live in California? 
3. Do 50 state tunes make less power than 49 state tunes?
4. Will 50 state tuning void my factory warranty?
5. Who is 50 state tuning made for? 


50 State Tuning Truck Pic 2-01


1. What's the difference between 49 and 50 state tuning?

The major difference between a 49 state tune and a 50 state tune is its compliance with C.A.R.B. or California Air Resources Board standards. To be considered true 50 state tuning the product must be issued an E.O. or Executive Order with a traceable E.O. number. To get an E.O. emissions testing must be performed in an approved facility and the paperwork must be filed with C.A.R.B. The process is relatively expensive, time-consuming, and can take years to complete. Your purchase of a 50 state tuning product will come with an E.O. sticker that provides information in the event of an inspection. This sticker must be placed under the hood of the vehicle and displayed in a clearly visible spot. Neglecting to do so can result in a vehicle inspection or smog check failure. 


49-state tuning is still designed in compliance with federal emissions standards and often meets CARB standards. However, without going through CARB’s rigorous testing and approval the tuning will not be considered compliant by those that enforce CARB standards. Ironically only the California Air and Resource Board has the ability to enforce these laws in the state. Thus defaulting us back to federal emissions standards in the remaining forty-nine states. 


2020 Powerstroke On Dyno Calibrated Power Logo

2. Do I only need 50 state tuning if I live in California? 

CARB standards have been adopted by a total of 16 states as well as some provinces such as Ontario. These states all require that new vehicles sold within them meet CARB standards. Although Currently, California is the only state equipped to enforce CARB standards. This could change at any time and you won't want to be caught with your pants down when it does. "When violations are substantiated, CARB may issue a citation, notice of violation, or equivalent document. In some cases, CARB issues a cease and desist letter that requires the responsible party to immediately refrain from the ongoing violation." - California Air Resources Board. Since California is currently the only state to enforce CARB standards, you will be required to run a 50 state tune if you live in or travel through the state. Even if you live in a state that does not follow the CARB standard and drive into a CARB standard state or province, you could be fined if inspected. While this is extremely rare, it is possible. Below is a list of states that have currently adopted CARB standards as of December 2022.


  1. California
  2. Colorado
  3. Connecticut
  4. Delaware
  5. Maine
  6. Maryland
  7. Massachusetts
  8. New Jersey
  9. New York 
  10. Oregon
  11. Ontario, Canada
  12. Pennsylvania
  13. Rhode Island
  14. Vermont
  15. Virginia 
  16. Washington 
  17. Washington D.C. 





3. Do 50 state tunes make less power than 49 state tunes?

49 and 50-state tuning power levels are more than often Identical. 50-state tuning however will not allow for other non-CARB certified aftermarket products to be installed on the truck. This means if you order a 50-state tune we can not tune for modifications such as modified injectors, aftermarket high-pressure fuel pumps, or upgraded turbos just to name a few. This will ultimately limit how much power you're able to build your truck to. Although you shouldn't have to sacrifice much if anything when it comes to performance gains from tuning alone.


2020 Power Stroke Ford Truck Black f250-1


4. Will 50-state tuning void my factory warranty?

Any aftermarket tuning has the potential to void your factory warranty. Although we have seen very few cases where a customer's warranty was voided due to tuning. This is because emissions-intact tuning only requires modification to the ECM. This means that with a hand-held flash tool, your tuning can easily be restored to the stock files your truck came with. This essentially restores your truck to its stock form if you need to take your truck in for warranty work. The best part about 50 State tuning is that it's as reliable and clean as an OEM file yet offers major performance advantages without sacrificing longevity or efficiency. Along with the decreased likely hood of aftermarket parts being applied a truck with 50 state tuning. The original stock file flashed back to the truck you should give you a greater likely hood of passing as stock at the dealer. 




5. Who is 50 state tuning made for?  

In general 50 state tuning is made for those that want a major performance upgrade for their truck yet still need to abide by CARB standards. For those that live in California, this is the only option you will have if you want to tune your truck and keep it on the road. As well as those that plan on driving their truck through states that enforce CARB standards such as California. It's also a good idea for those that live in states that have adopted CARB standards because enforcement could come at any time. It's also a very smart choice for anyone who wants to tune their truck but doesn't plan on upgrading other components such as injectors, turbo, or other parts that can impact emissions. 




Both 49 and 50 state tunes are great choices. What makes one better than another really comes down to how you want to use your truck. Both tunes must be tested and verified to be compliant with EPA standards. However, the scrutiny at which these tunes are evaluated is very different. 49 state tunes can be tested and verified to fall within EPA standards by the people or entity who created the tuning. While 50 state tuning must be put through extremely costly independent testing which holds it to the highest standards in order to prove the tuning does not increase emissions outputs. This gives 50 state tuning the credibility to allow vehicles equipped with it to pass emissions testing in the state of California. Along with making it one of the safest ways to improve a vehicle's performance. If being in compliance and or retaining reliability is something that matters to you, yet you still want to be able to make loads of power, then 50 state tuning is a perfect option for you. 
49 state tuning on the other hand can allow for other non-CARB-approved modifications to be fitted and tuned for. Which can improve the overall power derived from tuning. While it can oftentimes be just as clean and reliable as 50 state tuning. Its limitations lie in its lack of approval by CARB making it illegal to drive a truck with 49 state tuning in or through the state of California. While many other states have adopted CARB standards they have yet to establish enforcement for these standards. Making 49-state tuning perfectly fine to run in them for the time being.






California Air Resources Board (2020) California Air Resources BoardEnforcement Policy | California Air Resources Board. Available at: https://ww2.arb.ca.gov/resources/documents/enforcement-policy (Accessed: December 7, 2022). 

Topics: Emisssions Intact Tuning, Diesel Tuning, custom tuning, L5P Tuning, 50-state tuning