I am facing a strange issue with PCM on a 996 2004. The car loses all its setiings and memories when the ignition is switched off.

Has anyone come throught this before ?

TIA

 

.....bump

 

How is your battery? Original?

 

Battery is good. It starts the car well. Cant be it, as PCM only needs a very small amount of power to keep "thinking"

 

I suspect an internal PCM error. There is usually a line that is always on, then another line that is switched. The component will always 'draw power' from the constant line, but uses the 'swtiched' line to tell it to go off (technically standby), etc. Perhaps something got corrupted, or an internal fault, and when it goes to standby it doesn't write the current values to memory? I can think of may scenarios that might explain this. I would unplug the PCM for a hour or two, then reconnect. Past that, I wouldn't have a clue.

A

PS Of course there has been no modifications to the electrical system, recently or in the past, right?

 

so you reckon its an internal non fixable issue that requires exchanging the complete pcm unit ?
no mods or else done to the cars electrics

 

Any other electrical problems? The ignition switch can play havoc with all sorts of stuff.

 

Try testing the alway hot wire for power.

Removing and replacing the wiring harness may fix a faulty connection as well.

Start with the simple stuff and work your up to the more complex.

 

So disconnecting it and seeing if it 'resets' didn't work??

 

definitely check you battery.... that should reset the whole thing....