What are the chances of me throwing an emissions circuit short code because of a malfunctioning PCM?I've traced the circuit for damaged wire and replaced all components.Baffled.Need a 4.0 guru that has seen this kind of thing b4!!!thanks for reading.

 

Certainly possible, but there is no test for it, I guess you could pull the PCM connector and test wires for a "short", if they are OK then PCM circuit would be suspect, but need more info

What year Ranger?

And what Code?

 

1996 4.0 v6.code p0443,replaced purge flow solenoid,purge flow sensor/thermostat,and wire traced.the code throws every other key cycle.when it doesn't throw cel I can drive however and it won't cel,that being said I know the very next key turn immediately on start it will cell p0443.

 

P0443 Evaporative Emission Control System Purge Control Valve Circuit

So its a CIRCUIT code, not a pressure leak code

And computer did NOT use
P0444 Evaporative Emission Control System Purge Control Valve Circuit Open
P0445 Evaporative Emission Control System Purge Control Valve Circuit Shorted

So I would have replaced the Purge valve as well, just on speculation, but that doesn't always work

Did you happen to use a vacuum pump or "human pump"(blow thru the hoses on purge valve) to make sure the hose are clear no blocks?

If circuit is not "open" or "shorted" but has a problem then maybe it is because opening and closing the purge valve is not changing pressure in the gas tank, so "circuit problem"
Just a guess
I would check that the hoses are clear

And yes it can be computer that has the problem, long shot but can happen

 

Thank you 4 ur wisdom buddy.On a 16 hour work shift but as soon as I get time I will check my hoses for obstructions,I skipped that step isolating more towards electrical.