CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Oxygen Sensors

I have a 2001 Ford Ranger 2WD XLT. CAn anyone tell me how many oxygen sensors it has? I bought four (two upstream and two downstream) but my mechanic said there was only one downstream and installed three. However, the check engine light is back on saying “Too Lean.” Is it possible that they missed one of them or that all three were simply bad?

If it has the 3.0 liter engine there’s three O2 sensors. Two before the cat and one after.

If you’re getting a too lean code try cleaning the MAF sensor with MAF sensor cleaner. If the MAF sensor is dirty and is unable to detect the actual amount of air entering the engine, the computer compares the reading from the MAF sensor to the reading of the O2 sensors. And if the O2 sensors detect more air than the MAF sensor detects it’ll cause a too lean code.

Tester