I have a 2008 Toyota Yaris and the check engine light was constantly on with the known issue P0420! Mechanics would clear the light with OBD and use various cleaners like Tunap or Oxycat. However, after a few days, I noticed that the light would come back on! I tried this product with the gas tank at 1/4, cleared the light, put in a good 98 octane at a reliable gas station (through the fuel.gr app), and for quite some time now the light has not come back on! I will definitely buy it again!

Based on driving experience, I write that most of us are not mechanics.... I installed it before a long trip on a naturally aspirated engine after I burned a junk 100 and filled up at a good gas station. I drove about 1000 kilometers mostly on highways and a bit in rural areas with inclines and curves, with quite a few revs on the engine, and I feel that it really changed the throttle response

Very useful product because it simply does what it promises!!...with fault code initially P0420 (insufficient catalyst efficiency in short) and immediately after P1336 (ignition failure in cylinder 1), the car took a BREATH after using it with a full tank of gasoline (70lt), which was visibly noticeable especially after the first 100km... no comparison to before... like I just bought the car!! it stopped showing hesitation when pressing the gas, especially in 1st and 2nd gear and at low RPMs, and its horsepower returned!!.. in combination with 100 or 98 octane gasoline, the results would logically be even better from the start (the product test was done with 95 octane)... it goes without saying that those specific fault codes did not light up again... I highly recommend it!!... however, I believe that it should be applied at regular intervals (perhaps every 2-3000km) to maintain the catalyst's efficiency...

Very good product, I don't know how well it works, but it definitely gives more air in general to the engine

The car got clogged in an injection, I cleaned it in an ultrasonic cleaner and my mechanic told me to add injection cleaner after 2 refills, then to add catalytic system clean. The engine has an amazing idle and good pickup on the gas

I don't know, it didn't work for me; the same problem I had, I still have, and the error code keeps lighting up continuously from the day I started the medication until today, nothing has changed. I'm not saying the medication is to blame, it just didn't work for me

The engine light turned on after refueling with gasoline. I added a 100 octane gasoline and this additive, the indicator went off and it hasn't turned on again. It probably did something.

As I mentioned in another review, it is difficult to draw conclusions easily with just one use, whether it did the job or not.

As a brand and in terms of product quality, Liqui Moly is well-known in the automotive industry.

With just one use of this particular product, I cannot easily express an opinion.

Perhaps someone will notice a difference if they use this liquid more frequently, and not just after a few thousand kilometers as stated on the packaging.

For example, if someone takes a trip from Athens to Thessaloniki, they should use one container on the way there and immediately after, use it again on the return journey.

Perhaps this way, there will be a clearer picture with frequent use.

It was giving me a problem with the catalyst, so I decided to try the product. I added it to a full tank with the engine running, burned all the gasoline, and the error went away. So far, I have driven about 300 kilometers without the light coming back on, which would normally happen at 50 to 60 km... I will wait to drive more kilometers to see if it comes back on, and I will add an update here to give it a five-star rating. Edit... After 600 km, the light came back on again

I had no indication in the car. Gas measurements were normal. However, it constantly smelled like gas in the car for months. I filled the car with a 100 euro bill, put one of these in the tank, and after several kilometers, it never smelled again. Well done, honestly.

P.S. There is also a version that you spray into the intake, but I wouldn't risk it.

Very good product for those who want to clean the exhaust system. My car was showing a warning light with code P0420 indicating a problem with the sensor or catalytic converter, but after using this product, the light never came on again. It is also good to put it in the fuel tank.