Question

2002 Ford Escape 4x4 with engine code P1633. The engine light has not come on, any idea where I can start?

Answer 1

The P1633 indicates that you have an issue with the Keep Alive Power Voltage in the Powertrain Control Module. You should start by checking all the fuses. Here is more information about the code:

P1633 Ford Code - Keep Alive Power Voltage Too Low
Read more: https://www.autocodes.com/p1633_ford.html