CRC Guaranteed to Pass Emissions Test Formula, 12 Fluid Ounce

Ever since the new CA State mandate that older cars and trucks have to go to a Star Emissions Station for their smog check I have become very familiar with Guaranteed to Pass. The first year of getting smogged under the new regulations my 1995 truck barely failed. It’s a tougher series of tests and it really sucks to have to pay more for a smog test that is designed to get older cars and trucks off the road that would normally pass a regular smog check. It came at a bad time, having just been laid off and losing my health insurance and income and trying to figure how to come up with money for truck repairs to get my registration renewed so I could be a viable job candidate in the really bad job market of a few years back (and still today, may I add.) But that is a whole other issue that gets my blood boiling. So back to my experience with Guaranteed to Pass. My 1995 Ford Truck barely failed and I mean barely according to the emission numbers so I had the manifold cleaned out, used premium gas for a tank and added Guaranteed to Pass. Having two gas tanks was handy as I could switch the tank to a fresh tank without the remainder of the additive in it for the retest. It passed with flying colors. So for our other older 1993 mini-van and the truck in the few successive years since I always run the premium gas with Guaranteed to Pass in the tanks before the smog check. We’ve had the van and truck tested 3-4 times combined since and they pass every time. So I’m sold on Guaranteed to Pass and will vouch for it.

Used it as directed. Down to an eighth of a tank. Poured it in and added enough gas to get back to one half a tank. Wanted to get it mixed in really well. Immediately jumped on the interstate and ran 75 MPH for 40 miles. Stopped and filled the tank and when I restarted the engine, the light was off. Coincidence? Not a chance. Light had been on continuously for weeks. AutoZone said I needed a catalytic converter. Nope. One thing I found out the hard way. If your gas filler has a flap at the top, make sure it is easy to push aside. Mine had a little release button near the top that the filler hose would depress before the flap would release. Dumped the first bottle right on the ground. Twelve bucks wasted. No one to blame but me, I guess. Still a bargain, even at twice the price.

I read the specs on this product and it was guaranteed to cleanse as well as turn engine light off in vehicle. I received it March 14.2026 and used it on March 15.2026 I took a picture on Sunday before I entered it into the gas tank engine light was on at that time. Today is March 17.2026 and engine light is still on. The truck was driven for one hour on the 15th 45 minutes on the 16th and 50 minutes on 17 March. Still the engine light is on. Got home parked the vehicle took a picture again to show engine light is still on product guaranteed it was shut it off, but unfortunately product does not work.

Sadly, Didn't work for me

I’ve had this product work before, and it’s been good. This time it did not, and I actually used the warranty/guarantee process and they stood by their assurance and refunded me! I would absolutely buy the product again, my car is a 1995 BMW with <75k miles and it failed CA smog, but using this made it pass before. After the failure this time I had the car checked and it needed an O2 sensor, which fixed it for good, hopefully. But I would absolutely recommend this product to others - if the car isn’t suffering from something major, it DOES work! And the company stands behind it.

I did not pass and followed instructions to the T.

This product never fails (no pun intended), I have been using this for the last 10 years my car has never failed a smog test. I highly recommend this and that you use it correctly. You will not be disappointed.

My 1997 Chevrolet Venture minivan failed the California smog test for the first time due to high NOx emissions. Doing a search on the internet I found the likely causes to be a clogged or sticky EGR valve, upstream O2 sensor and carboned combustion chambers. The EGR valve and upstream O2 sensor are both the original parts so I cleaned the EGR valve which was a little sticky and replaced the upstream O2 sensor. Lastly, I added a bottle of CRC Emissions Test Formula to the gas tank when it was half full and followed the rest of the instructions on the box. Passed the retest with NOx reduced by 50% from the original readings and HC also reduced. Not sure what the main contributor was in getting a pass for the 2nd smog test but I think a bottle of the CRC Formula was worth it as an added measure especially considering CRC's double your money back guarantee.

The engine check light disappeared for two days and came back. Before every time I reset the error code the engine check light would not come back before few days, but after using this product the it would come back next drive.

Simply, absolutely works. Your car will run great again with increased gas milelage too.

A fruend called me anout her MIL/Enginel light coming on. P0 420 came on i think. O2 sensor bank 1. Exhaust had good pressure so catalytiv wasnt plugged up. So bought some of this and her light went out i assume bevause she said its ok (shes vietnamese with not the best English) and hasnt mentioned it in last 3 weeks. I bought a few more to give her some for next time when needed and for my 09 small truck.

Useless. Not worked

I tried this to keep my CEL off. I can clear my P0430 code with a code reader and the CEL stays off for a day. This made my code stay off for 2 days before returning. Not was I was hoping, but would work for someone just trying to pass an emissions test. My cat must be no good.