The most common cause of a P0102 on a 2010-2015 Toyota Prius is user error. How does it happen? Maybe an oil change place wanted to check the air filter, or maybe an owner wanted to service the throttle body. Regardless of how it happened, the most likely cause of a P0102 is an unplugged air flow meter. It’s the part on the top of the air cleaner housing with wires and a connector.
This connector plugs in from the underside and when it’s unplugged, it’s not that easy to see. It may also cause a P3190 or P3191 and P0A0F, since the engine may hot start without this critical input. However, Toyota does have a failsafe and uses throttle position to estimate the amount of air entering the engine. It’s actually better to have not MAF input than a wrong MAF input.
Toyota Prius P0102 can have other causes
Maybe your Prius just developed a P0102 all on its own. No recent oil change or any other service work.
Mice love the Prius because it’s a green car. No joke. Much of the wiring insulation is soy based and the mice seem to prefer it to older wire. Why do they nibble all the way through the copper? I don’t know, mice aren’t my area of expertise, but I do have Google.
Apparently rodent’s lower teeth continue growing forever. If they don’t gnaw on something, their teeth will grow into their brain, which makes them motivated chewers. Rodentem in latin means “the gnawers”. You learn something new every day. Here’s a rodent fact sheet if you’re interested.
How to repair
Once the wire is chewed up, I’m the guy you should call. Unless you’re skilled with wiring repair I’d recommend having a mechanic do the repair. If you’re interested in seeing how we repair the wiring, here’s a link.
Can other things cause Prius to throw a P0102? Yes, theoretically, but they’re not common. The MAF sensor may be bad, or the ECM may be bad, but it’s not very likely. If you do end up replacing your MAF sensor, buy either Denso or from a Dealer. You DON’T want an aftermarket sensor. Trust me on this.
If you replace the ECM (and you shouldn’t; it’s not the problem), then you’ll need to have us or another mechanic program the ECM to the most current software version.
That’s it! That should help you find and fix the cause of your Toyota Prius P0102.