What is engine check code P112 on a 99 Mazda 626lX V6 engine?

There is no standard OBD-II trouble code P112. OBD-II codes are typically three or four digits. A code starting with "P" indicates a powertrain system problem. It's highly likely that you have either:

* Misread the code: Double-check the code displayed on your OBD-II reader. A single digit off can make a huge difference. Try clearing the code and seeing if it comes back.

* Obtained a manufacturer-specific code: Mazda might use a code that's not in the standard OBD-II database. In this case, you'll need a Mazda-specific diagnostic tool or consult a Mazda repair manual.

To find the correct code, you'll need to use a reliable OBD-II scanner. If you've already done this and are certain the code is P112, you'll need to consult a Mazda-specific resource. Mazda's service manuals or a specialized Mazda diagnostic tool would be necessary to decipher this.