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Electrical gremlins


6 Dec 2020
Not sure if these are related....but noticed both at same time.

Context...2004 996.2 tt tip. Was off road a bit doing work...battery definitely ran low at times but e.g. trip mileage not reset.

Issue 1 - clock keeps going down 1 hr shortly after start. Not sure if this some summer time/gps thing (does the 996.2 have that?)

Issue 2 - the stereo started either not coming on or taking a lot of time to come on (like 10mins+). When it does come on the preset number pad and few other buttons dont work. Some buttons do e.g. frequency search...

Frustrating and odd. Any tips?


Ok .. well i'm afraid both faults are related .. the PCM is in charge of the time shown in the instrument cluster ..

The pcm takes ages to actually start working and it's giving incorrect info to the instrument cluster .. this to me indicates a problem with the pcm it self .

basically this unit has an earth wire , a battery 12 volt feed and an ignition 12 volt feed .. unless something like the ignition switch is not giving it a 12 volt feed .. but is 10 mins later then its the pcm at fault ..

Btw .. ignition switch causing this whilst possible would be a new one on me .

There was a post recently on where to send these units to be repaired ... not sure if 997 or 996 but the same place can repair them .


The only things an Indy could do was check the ignition feed and do a vehicle handover .. a .. well .. a basic wakeup of items but it's more like turning them off then back on again .

Im dubious it will make any difference but thats all i would do before sending the unit for repair .
Thanks as ever DeMort.

Only things I am going to try are 1) pull the fuse in the box...2) replace the fuse behind the unit (since the unit isnt even lighting now). Not hopeful.

I have a new head unit anyway...so i guess it might just be time to get on with that job....and send the pcm off for check.



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