loss of power "check engine light on

Many times a code wont be the actual part as the code can refer to a system or circuit. A common one that I have fixed a few times is O2 sensor codes. Its not the O2 sensor, its dirty fuse connections for the heated side of the O2 circuit. Ecm sees a false resistance and sets a code.


http://www.justanswer.com/chevy/234yx-p2135-pedal-position-switch-a-b-voltage-connection-error.html

http://repairpal.com/obd-ii-code-p0120