Woman’s Check Engine Light Comes On. Then She Uses Cataclean From O’Reilly: ‘I Think It Cost Me $27’

The check engine light on a California woman’s car came on. Instead of rushing to her mechanic, she used Cataclean from O’Reilly Auto Parts. The move may have saved her money or just bought her time.

TikTok creator Nat Banda (@natbanda) posted a video asking for advice on the subject. “I'm due for a smog check and my check engine light is on,” she says to start the video. “I did run it through the scanner and it gave me the 420 code, which is emissions. So something to do with my catalytic converter.”

Nat doesn’t have the money to get to a mechanic just yet, so she tried a DIY solution. “So what we're going to do is try this thing here,” she says. “It's called Cataclean. It's supposed to turn off my check engine light and help me pass the smog [test].”

Does Cataclean Clear The Check Engine Light?

The TikToker acknowledges that Cataclean is a temporary fix, and even if it is effective, she will still need to have her car checked by a mechanic.

“But for now I just need to get my tags,” she says. “So let's see if it works. In case you're wondering, I got this at O'Reilly. I think it cost me $27-$28, maybe. You basically have to be at a quarter tank of gas and then you have to drive for 10-15 miles and yeah that should do it.”

The video cuts to a series of clips of Nat driving that distance. “We've officially hit 10 miles,” she says. “The check engine light is still on. I'm crossing my fingers that it turns off soon.”

The video cuts to yet another clip. “After driving the car for 15 miles, the check engine light is still on,” she says. “I decided to drive it a little more, and unfortunately it has not turned off. That's a bummer. What we're going to do is we're going to fill up the tank and hopefully in the next couple of days the light goes off.”

What Exactly Is Cataclean and What Does It Do?

According to Cataclean, the product is a cleaner that removes carbon, resin, and gum build-up from a vehicle's fuel and exhaust system. It is supposed to help with catalytic converter issues, catalyst codes, and EGR valve issues.

Cataclean removes deposits as it passes over the components in the exhaust system, creating an acidic vapor of carboxylic acids that clean the oxygen sensors, EGR valve, catalytic converter, and exhaust.

In a Reddit thread posted to r/mechanics a couple of years ago, commenters generally agreed that Cataclean’s effectiveness depends largely on the severity of the exhaust system issue. 

"I've had it work and had it not seem to make a difference," one person wrote. "I've used it personally and recommended it as a cheap Hail Mary to dozens of customers. I'd say it works 10-20% of the time."

Motor1 contacted Nat Banda via TikTok comment and direct message for comment. We also contacted Cataclean and O’Reilly via email for comment.