Can 1 engine code be a result of other engine codes

Question

I have codes P0171, P0174, P0720, and P0455 come up on my 1998 Ford Explorer, also my overdrive light is blinking on and off.

Answer 1

The codes are unrelated. You have issues in the transmission, the engine and the emission/evap system.

First, P0171 and 174 are lean fuel mixture codes. These are usually caused by a bad mass air flow sensor, intake manifold leaks or a problem with low fuel pressure.

Then the P0720, this is an output shaft speed sensor code. This can be serviced as it is bolted to the outside of the transmission and usually replacing it will resolve the issue

Finally the P0455, this means there is a possible leak in the evap system or a problem with the purge control solenoid valve. A smoke test is usually done on the system to located the leak