Liqui MolyCatalytic System Clean 300 ml 7110. Cleans The Injection System and The Combustion Chamber.

I have a 98 Rav4 with 319k miles and my engine light went off with the PO 420 code, right around the time I needed to get emissions. I bought this stuff on its high recommendations, following sometimes instructions if putting it in with a half tank and driving about 100+ miles and then took it in for the test. Passed with flying colors. Highly recommend! And plan to purchase again in the future for regular maintenance on my vehicles.

This is great stuff! Worked perfectly. Realize that if you get an error code (420 or 430? I forget) for the catalytic converter, the code is simply stating that the efficiency of the converter/sensors is below 95%. So only a 5% reduction yields an error code. The Liqui Moly obviously cleans the converter/sensors to enable a 95% or better efficiency...did it clean only 1% or more? who knows, but my code is gone and I am very pleased with the product.

Made an instant difference

Chrysler town and country 2005. Engine light on for months. After add this product to tank. Engine light gone and drive smoother. It is helpful

Was able to past my inspection, had an error on CAT, one bottle worked. Been driving 55mph trying to hold for 3 mins for about a week and it still did not work, put this in to my tank tried again and passed. Comes in a durable can and the attachment is a huge plus since my car had a capless fuel opening, this was able to bypass the clamps to open out my fuel intake. Very simple to use, but be careful this stuff is not safe to smell very strong fumes. Good value for the money.

Used it on 2004 Lexus RX330 with 275,000 miles. PO4 light went out and has been off for over a month.

It was very easy to use. But I've driven a couple hundred miles since I used it. Check engine light (P0420) is still on and I haven't noticed any improved efficiency. Just a waste of money.Update January 2025: Didn't know why it took so long but the check engine light did end up popping off and stayed off for a couple thousand miles before coming back on. Willing to give it a second shot.

Got a catalytic converter low efficiency code? (P0420 or P0430 - most often) For the price, this is worth a shot. Something not mentioned in the directions that will help this work better: Use it over longer trips so that your catalytic converter has a chance to get up to, and run at operating temperature with this coming through the fuel system. If you add this and then only take short trips, it's not going to be very effective.Also note that the P0420/0430 code often can't be cleared manually, and usually requires one or more successful catalytic self-tests to execute before the code clears. The vehicle usually needs to be ran for at least 20-30 minutes before the test begins.In my case it worked, but the code was just on the edge of cycling on and off over the course of several trips, meaning that the self-test was passing half of the time before treatment.