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Registered
Join Date: Feb 2024
Posts: 2
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2013 Porsche 991 No Start
2013 991 3.4L 22K miles
I have an issue with no start on my 991. The car was sat in the climate controlled garage for 4 months on a battery tender. The symptoms as follows. Battery at 12.1 V, Key in and turn to run position. All lights, radio, windows, dash indicators function as normal. PDK in park, foot on brake and key to start. Nothing. No change in dash lights, no clicking, nothing. Car key remote will lock and unlock the doors. Some diagnostics as follows 1) Used FOXWELL scan tool and see DME fault code P3052 Starter relay (upper limit relay activation. Cleared codes. Check and all codes cleared. Try to start. Same signature and P3052 reappears 2) Main battery was very old and seemed to discharge somewhat rapidly. Replaced with new battery. Cleared codes, Still same signature 3) Replaced key fob battery (even though no dash message) Still nothing. 4) Removed start relay and bench test. Passed the test. 5) Turned key to run position and jumped across start relay terminal 30 which had +12 V and terminal 87 (to starter). Engine fired up and ran until I turned key off. At this point I suspected the start relay contacts so I purchased a new one (Porsche part) 6) Installed new start relay. Still nothing. 7) Checked terminals on start relay with it installed. Terminal 86 (from front BCM according to wiring diagrams is +12 V with key to start 8) Checked terminal 85 on start relay and nothing. It is supposed to be ground/earth from DME according to the drawings. 9) The only thing that I am aware of to make the DME send the grounds signal is foot on brake and trans in park or neutral. I can see the dash warning for no foot on brake or trans not in park or neutral when I turn key to start and message go away when I apply the bake or switch trans to P or N. 10) I went back to the FOXWELL scanner and looked at real time data from DME and could see the parking brake and trans shift position satisfied. So now I am stuck in not knowing where to go without a PIWIS to maybe look deeper into the DME. I also tried to set off the alarm and silence with key to maybe reset the immobilizer. Still nothing. I am not sure if the DME needs some other things satisfied before ground is sent to terminal 85 I am at the point of taking the car to the shop but thought I would see if anyone had any other ideas of things to check. Thanks in advance. |
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Registered
Join Date: Feb 2014
Location: Lomita, CA
Posts: 2,694
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So another no-crank, right? Seen this problem in the 991 DME ECM, as a bad signal to the crank relay.
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Dave |
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Registered
Join Date: Feb 2024
Posts: 2
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Quote:
Not sure why or what to do next other than send to shop with PIWIS |
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