Guaranteed to Pass Emissions System Cleaner Fuel Additive - 12 oz

It has worked every time I've used this product. Won't fix a damage catalytic converter but will help you pass the test if your car almost passed.

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.

I've used and it's worked for emissions for me and that's with having check engine light on..use stuff,drive around a bit,clear code drive to emissions and should b good unless got serious problems. It's good to use 1 or 2 times a yr if high mileage vehicle.

My 2005 Jetta failed the inspection and my mechanic said (after clearing the engine light) that I should drive the car for 20 min highway and 20 local. We've tried that the whole day but out of three lights on his device only 1 went away. Next day the light engine came back. After not being happy with the explanation offered by him (a family friend) that I should keep driving it until we get lucky I went online and found CRC 05063. Followed the instruction (one bottle on full tank of gas). Before my tank was under 3/4, engine light went off!! At half tank I went and did the inspection - IT PASSED! I am really impressed! Update August 2015! I have been using this product for 2-3 years now and if it is not working for you please read. In July I have used the first bottle and took my 2005 Jetta for inspection. It failed. Ordered a second bottle and it failed again. My mechanic said keep driving. Did 200 miles in one day and nothing. Decided to take matters in my own hands and ordered Autel MaxiScan MS300 ($18, it allows you to read and delete codes). There were two faults - EVAP and 2nd something about Oxygen. Went online and this is the first time I heard about driving cycles. These are steps that you have to follow so that your car's computer can start measuring all the parameters needed for the test. Driving cycles are not exact science but I tried to follow the instructions as much as I could and after just 20 minutes (10min city and 10min highway) ALL the parameters were set and I passed the emission test with flying colors! So, just before you give a comment about CRC like "tried and didn't work" be aware that there are other things you have to take into account.

My car didn't pass. However, the company CRC sent me a reimbursement check.

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.

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.

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.

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.

Useless. Not worked

works as advertised. I drive mostly around town and the system was carbonized. Vehicles need some highway driving to help clean out the system..