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Random electrical issues causing no start.


Herc

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08 997 TT, 5800 miles, just got the car in Nov. Drove it a few times then one day I went to start and got "depress clutch", tried a few times and it started.

Replaced the clutch micro switch, drove it the next day and when I tried to start later, key on-"PSM" and "ABS" fail, key to start "depress clutch". Left it for the night and came back with a new battery, Interstate 94r, started fine. Next time I drove same issue again, sometimes get a few more fault messages but always "PSM" and "ABS" at key on and "depress clutch" at key to start.


Took it to the dealer, no warranty, long story as the car has Champion 700 kit, tech says sometimes it starts and sometimes it fails as above. They replaced the PAS module, clutch cruise switch and brake switch. I had the DME tested and re-flashed, tech disconnected and cleaned all ground points and checked all relays. He still says he can get it to fail every 6 to 9 key key actuations.

Waits a while and recycles the key and it starts. Sometimes the PIWIS "sees" the DME and sometimes it doesn't when it fails, still shows code 15sv, no start voltage.


Stranger yet, tech says when he disconnected a buss bar under the drivers side dash and manipulated it and it's wires he was able to get it to fail on cue, not sure which wires, he is going to look into it, but when I was able

to get it to restart I had been under there moving pedals and wires??????


Waiting for PCNA to get back to him, they no longer will talk to me.

Anybody have any ideas?

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What codes did the tech pull with PIWIS?

It only shows a code when it fails, then it shows a 15sv which is lack of ignition power, "no 15 power". When it doesn't fail nothing shows up.

The way he explained it to me was the PAS, immobilizer module, is looking for 15 power from the DME, if it doesn't get it then the PAS won't

allow the car to start. But there seems to be other things going on also.

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Took it to the dealer, no warranty, long story as the car has Champion 700 kit, tech says sometimes it starts and sometimes it fails as above. They replaced the PAS module, clutch cruise switch and brake switch. I had the DME tested and re-flashed, tech disconnected and cleaned all ground points and checked all relays. He still says he can get it to fail every 6 to 9 key key actuations.
Waits a while and recycles the key and it starts. Sometimes the PIWIS "sees" the DME and sometimes it doesn't when it fails, still shows code 15sv, no start voltage.

Whenever I see the words "random" and "electrical" I go right for the battery and chassis grounds. And 997-1 has a known battery cable problem.

I totally agree Loren. One would think a dealer tech would have done that first since he DME tested and re-flashed, tech disconnected and cleaned all ground points and checked all relays.

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DME has a GIAC flash and I sent it in for testing and a re-flash. All battery connections and grounds have been checked and cleaned. Seems to

me that something is telling the PAS that the clutch isn't depressed along with the PSM and ABS fail. Again, it doesn't happen all the time which

makes me suspect a wiring issue on the drivers side. I had originally thought voltage/battery issues but that seems to have been ruled out now.

Waiting to hear from the PCNA "expert", another option is the Porsche $600 "loaner" DME to rule that out 100%.

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Are there any other aftermarket electronics in the car. IE: alarm, radio, nav.?

No. Just the engine performance kit from Champion Motorsport with a GIAC flash. It does have extra led driving lights up front and a full .2

rear bumper and lights with GT-2 wing. The car had no problems since 08 in Fla, then when it shows out here in Utah and 20 to 30 degrees F

it starts having issues. Car was fully inspected, CPO inspection, by the dealer i bought it from with no issues. PCNA is not honoring the CPO

and sending my money back, my local dealer, Dave Strong, whined about the extra parts on the car, they have a history of this.

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I have some ideas however before I say anything I need some more info. Also before you condemn the DME lets go back to basics. Please give a full history of the car. How long have you owned it and when did you start having this issue? You say the all battery connections and grounds have been checked and cleaned. By who and did that person do a voltage drop test to both power & ground side of that system or just Ohm out the the system? It sounds like you sent out the DME to be re flashed by Champion Motorsport correct? The dealer did not do any testing or re flashing? Think about what changed in your normal routine when you moved to Utah besides the temperature.

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I have some ideas however before I say anything I need some more info. Also before you condemn the DME lets go back to basics. Please give a full history of the car. How long have you owned it and when did you start having this issue? You say the all battery connections and grounds have been checked and cleaned. By who and did that person do a voltage drop test to both power & ground side of that system or just Ohm out the the system? It sounds like you sent out the DME to be re flashed by Champion Motorsport correct? The dealer did not do any testing or re flashing? Think about what changed in your normal routine when you moved to Utah besides the temperature.

I don't think it's the DME. I bought the car last Nov, 1 owner from South Fla, the 1st owner had Champion Motorsport install the 700 Werks One

kit along with led driving lights, .2 rear facia and led lights, GT2 wing and 20 in Champion wheels when the car was fairly new, this included

the GIAC flash for the mods. I have the full maintenance history, 5600 miles when I bought it and it has had 4 to 5 oil changes, clutch slave

replaced, battery replaced Aug 13 and a few 'campaigns" done at the dealer.

I received the car early Nov 13, the first 3 times I drove it there were no issues, it did give me the "depress clutch" once when trying to start

but nothing else and started when I recycled the key.

Drove it one day to a part time job i have and it sat outside in 20 to 30 F degree weather, went to start it at lunch time and got- key on then

"PSM" and "ABS" fail along with "oil temp inop", key to start and got "depress clutch". Let it sit until I got off and the same thing so I got up

in the drivers foot well and manipulated the pedals and clutch switch along with some wires, got it started.

Next day I replaced the clutch micro, not the cruise disconnect, seemed to work fine. Drove to my friends house for Thanksgiving and it sat

outside for a few hours again in 20 to 30 F. Went to go home and same as above. Next morning I went back and changed the battery, not

knowing it was new in Aug, installed the Interstate 94R, started fine and off to home. Next outing same thing, this time I repeatedly manipulated

clutch and brake switches and disconnected the neg cable on the battery, key on then off numerous times, after about 30 min I got it to start.

Next day started in the garage and let it run for 30 min, at this time it was starting fine first thing every day, noticed that the right rear tail light

only had half of the leds working and that the brake lights were not working. Tested the battery while running and it was showing about 14.5v

with 12.7 with engine off. Thought I noticed the instrument back lighting not working also.

Took to Dave Strong Porsche here in Salt Lake. As soon as I got there I went to restart and same issue and was able to get the tech to come

out and see the same. Later they told me the brake lights were working fine and it started the next morning but not in the pm. Tech hooked

up the PIWIS when it wouldn't start and was showing "no comm" with the DME and no "15 power" (15sv code) like the DME wasn't even there.

he thought it was the PAS module as he had disconnected it a few time and got the car to start, so he replaced the PAS (immobilizer) module

and thought he had it fixed but it failed again.

Tech was thinking it was the DME, talked to the guru at GIAC he he said it could be. I sent the DME to Champion Motorsport and they, working

with GIAC, ran a bunch of tests on it including opening it up and looking at it under a microscope, it all worked fine, they also re flashed with

new software to rule out a bug.

DME reinstalled by the local tech and still fails randomly. Always key on "PSM" and "ABS" fail, key to start and "depress clutch" no start. Tech

then unhooked and cleaned all the grounds, checked the relays, replaced the clutch "cruise disconnect" switch (he said he was getting weird

resistance reading on it), swapped out the brake switch and ignition switch and still is able to get it to fail every 6 to 9 key cycles. He said he

had disconnected some buss bar/mulit wire mount up under the drivers side and while manipulating it was able to get the car to fail or pass.

He is thinking there is possibly a bad wire up there somewhere and is waiting for PCNA to get back with him so he can talk to one of their

experts.

My thoughts as of now. Something is telling the PAS that the clutch is not depressed and something seems to be telling the PAS there is no

"15 power", ignition power, not sure where the PSM and ABS come into play. But this only happens randomly so sounds like a bad connection

somewhere. I just wish I and the tech new what talks to what at key on and key to start. That is what he is hoping to get from PCNA.

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I have some ideas however before I say anything I need some more info. Also before you condemn the DME lets go back to basics. Please give a full history of the car. How long have you owned it and when did you start having this issue? You say the all battery connections and grounds have been checked and cleaned. By who and did that person do a voltage drop test to both power & ground side of that system or just Ohm out the the system? It sounds like you sent out the DME to be re flashed by Champion Motorsport correct? The dealer did not do any testing or re flashing? Think about what changed in your normal routine when you moved to Utah besides the temperature.

I don't think it's the DME. I bought the car last Nov, 1 owner from South Fla, the 1st owner had Champion Motorsport install the 700 Werks One

kit along with led driving lights, .2 rear facia and led lights, GT2 wing and 20 in Champion wheels when the car was fairly new, this included

the GIAC flash for the mods. I have the full maintenance history, 5600 miles when I bought it and it has had 4 to 5 oil changes, clutch slave

replaced, battery replaced Aug 13 and a few 'campaigns" done at the dealer.

I received the car early Nov 13, the first 3 times I drove it there were no issues, it did give me the "depress clutch" once when trying to start

but nothing else and started when I recycled the key.

Drove it one day to a part time job i have and it sat outside in 20 to 30 F degree weather, went to start it at lunch time and got- key on then

"PSM" and "ABS" fail along with "oil temp inop", key to start and got "depress clutch". Let it sit until I got off and the same thing so I got up

in the drivers foot well and manipulated the pedals and clutch switch along with some wires, got it started.

Next day I replaced the clutch micro, not the cruise disconnect, seemed to work fine. Drove to my friends house for Thanksgiving and it sat

outside for a few hours again in 20 to 30 F. Went to go home and same as above. Next morning I went back and changed the battery, not

knowing it was new in Aug, installed the Interstate 94R, started fine and off to home. Next outing same thing, this time I repeatedly manipulated

clutch and brake switches and disconnected the neg cable on the battery, key on then off numerous times, after about 30 min I got it to start.

Next day started in the garage and let it run for 30 min, at this time it was starting fine first thing every day, noticed that the right rear tail light

only had half of the leds working and that the brake lights were not working. Tested the battery while running and it was showing about 14.5v

with 12.7 with engine off. Thought I noticed the instrument back lighting not working also.

Took to Dave Strong Porsche here in Salt Lake. As soon as I got there I went to restart and same issue and was able to get the tech to come

out and see the same. Later they told me the brake lights were working fine and it started the next morning but not in the pm. Tech hooked

up the PIWIS when it wouldn't start and was showing "no comm" with the DME and no "15 power" (15sv code) like the DME wasn't even there.

he thought it was the PAS module as he had disconnected it a few time and got the car to start, so he replaced the PAS (immobilizer) module

and thought he had it fixed but it failed again.

Tech was thinking it was the DME, talked to the guru at GIAC he he said it could be. I sent the DME to Champion Motorsport and they, working

with GIAC, ran a bunch of tests on it including opening it up and looking at it under a microscope, it all worked fine, they also re flashed with

new software to rule out a bug.

DME reinstalled by the local tech and still fails randomly. Always key on "PSM" and "ABS" fail, key to start and "depress clutch" no start. Tech

then unhooked and cleaned all the grounds, checked the relays, replaced the clutch "cruise disconnect" switch (he said he was getting weird

resistance reading on it), swapped out the brake switch and ignition switch and still is able to get it to fail every 6 to 9 key cycles. He said he

had disconnected some buss bar/mulit wire mount up under the drivers side and while manipulating it was able to get the car to fail or pass.

He is thinking there is possibly a bad wire up there somewhere and is waiting for PCNA to get back with him so he can talk to one of their

experts.

My thoughts as of now. Something is telling the PAS that the clutch is not depressed and something seems to be telling the PAS there is no

"15 power", ignition power, not sure where the PSM and ABS come into play. But this only happens randomly so sounds like a bad connection

somewhere. I just wish I and the tech new what talks to what at key on and key to start. That is what he is hoping to get from PCNA.

I hate to come into this discussion so late, but one thing I would consider is to re-flash the DME back to stock. I am not a big fan of anyone's aftermarket flashes for exactly the reason you are suffering through: They all seem to have differing levels and types of problems. We have seen re-flashed cars that would not communicate with state inspections systems, we have seem them throw weird codes and MIL's; all of which disappeared when they were returned to the stock OEM programs.

The 997TT is a pretty wicked car in it own right as it comes from the factory. So I would take it back to stock and see if the problems disappear.

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This subject is an area which I've learned more about than I wish I ever had to. You're not going to want to hear it, but JFP is right. Trust me on this, if you're sure your wiring is all in good shape as Loren alluded to (each cable in the series to needs to be tested so check and double check the work on this, there have been some good write-ups how to do it), and you're still having these "random" issues and it's telling you it can't communicate with the DME, for example, I would definitely go back to the stock flash immediately to see if your problems go away. It should be very easy to re-flash to stock to test this. Takes 5 mins with a PIWIS. Literally. Or if you live close to your tuner, most tuners keep stock flashes on hand and some tuners even allow for switching between stock and custom tunes with a device (Revo SPS comes to mind--biggest piece of !@$% ever by the way, I hate that company with a passion).

I don't think PCNA is going to be much help. They are going to tell you that it's not their flash and you have molested the OEM state of the vehicle and your warranty is void. Running these myriad of aftermarket flashes can cause all sorts of headaches not limited to this. You're taken a known, tested, proved software configuration and modified it. As with any kind of software, just like on a PC, there are millions of things that can go wrong when you make just one little change. This is why it's so key having a configuration that has been tested so heavily, like the OEM stock flash. No tuner can match that. What I have seen first hand in the tuning world frankly scares the daylight out of me. People put faith in these guys like they are Gods and it's really not like that. I have first hand experience with similar types of issues and going back to stock fixed the issue immediately. Also, for what it's worth, I never could tell the difference with the tune off. She still ran like the wind.

Edited by Silver_TT
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As far as a re flash, the loaner DME is an option after I hear what they come up with next week. Both Champion Motorsport and GIAC have a

pretty good rep and with the mods on the car, (GT3 TB, 65mm turbos, larger intercoolers etc..) I'm not sure if factory software will work. If it was

the software you would think there would have been a problem in the last 5800 miles. Now the DME having an internal fault I might buy, cold

solder fault, but it is strange that manipulating electrical components and wires in the drivers foot well area seems to affect the problem.

If nothing comes out of next weeks problem shooting I'll go with the loaner DME with stock tune and see if that makes a difference, if so then

it would point to an internal fault in the current DME which would not be caused by different software but I will still need a new DME.

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I agree with JPF & Silver TT,

Regarding the aftermarket re flashing. I can tell you that most of the issues I see in the field is because of bad aftermarket components or poor workmanship. On the flip side I have a hunch. I see there is one thing in common with your issue your DME, PAS, PSM, ABS are all on the drive CAN bus that communicates though the combi/gateway (Cluster). You had said that the tech could could make it fail if playing with under dash splice pack. you also mentioned that "Thought I noticed the instrument back lighting not working also". If the OEM re flash dose not solve the issue I would check the connectors for those systems that lead to COMBI / Gateway. I would also suspect the COMB / Gateway (Cluster) is going south as its not uncommon for this car.

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Thanks for all the input so far. Champion Motorsport does a lot of these cars and from talking to them they have not seen this problem unless it

had something to do with grounding issues not DME issues, not that it couldn't.

I have owned numerous vehicles with tuned DMEs, Ducatis, Harleys, Vipers and other Porsches, never had a software tune problem that usually

shows as some sort of drivability issue, surging, missing etc. My problem is faults from other systems, not sure what bad DME software would

have to do with a "depress clutch" message. I was also surprised that nobody at this dealer know about the 30s override for a bad clutch micro

and the ensuing "depress clutch" message.

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How are you sure there was no problem ever before you got the car? I don't see how it's possible to know this for sure unless you know the previous owner personally and trust them. The problem should have nothing to do with the lower temperatures where you are, etc, which means if this really only first happened right after you took possession of the car, it's a pure coincidence. As a matter of fact if this is an electrical problem, which we already mentioned to look at closely, these usually get worse as temperature gets higher (aka increased resistance) -- NOT as temp gets lower.

Get a new loaner DME if you want. The memory on these cars can be flashed and reflashed over a thousand times and it would take a lot less work than swapping out the DME, but you can do it either way. I don't see how if a new loaner DME solves the problem though you think this points to a hardware fault in the current DME you have. The odds of you having a hardware fault are pretty low (unless your car has specifically been flooded or had moisture in it, etc). The odds of behavior like this due to a flash, regardless of the tuner's reputation, is much more probable. Not saying the flash is for sure your problem, but I've been down this road. I personally would never run a flash because of the issues it can create.

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I agree with JPF & Silver TT,

Regarding the aftermarket re flashing. I can tell you that most of the issues I see in the field is because of bad aftermarket components or poor workmanship. On the flip side I have a hunch. I see there is one thing in common with your issue your DME, PAS, PSM, ABS are all on the drive CAN bus that communicates though the combi/gateway (Cluster). You had said that the tech could could make it fail if playing with under dash splice pack. you also mentioned that "Thought I noticed the instrument back lighting not working also". If the OEM re flash dose not solve the issue I would check the connectors for those systems that lead to COMBI / Gateway. I would also suspect the COMB / Gateway (Cluster) is going south as its not uncommon for this car.

Thanks. I was originally thinking something like that after downloading Porsches electrical diagnostic pamphlet but the tech keeps going back

to the PAS as the controlling hub so to speak. I mention that to him next week.

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How are you sure there was no problem ever before you got the car? I don't see how it's possible to know this for sure unless you know the previous owner personally and trust them. The problem should have nothing to do with the lower temperatures where you are, etc, which means if this really only first happened right after you took possession of the car, it's a pure coincidence. As a matter of fact if this is an electrical problem, which we already mentioned to look at closely, these usually get worse as temperature gets higher (aka increased resistance) -- NOT as temp gets lower.

Get a new loaner DME if you want. The memory on these cars can be flashed and reflashed over a thousand times and it would take a lot less work than swapping out the DME, but you can do it either way. I don't see how if a new loaner DME solves the problem though you think this points to a hardware fault in the current DME you have. The odds of you having a hardware fault are pretty low (unless your car has specifically been flooded or had moisture in it, etc). The odds of behavior like this due to a flash, regardless of the tuner's reputation, is much more probable. Not saying the flash is for sure your problem, but I've been down this road. I personally would never run a flash because of the issues it can create.

Thought about having them flash mine back to stock but if it didn't work he would still suspect the DME it's self. Not sure how the car would run

on a stock flash with the mods.

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It depends on how they remapped the DME. It may not run great but If it fixes the starting issue you will know its the flash. Also I just looked at one of my venders I use for Instrument Clusters look whats at the top of the list.

http://www.bba-reman.com/content.aspx?content=hints_and_tips#porsche

Only thing I see on the list for a 997 was a clutch actuator, says won't go into gear?

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Please let us know what happens when you have the stock flash on there (through a reflash, or by replacing the entire computer). As stated, I don't think you need to worry too much about how the car would run with the modified hardware + the stock tune, as this should tell you right away if these issues go away before you even start the car. From what you have said, this happens frequently (< 10 tries) and the PIWIS won't even communicate with the DME....and this is all happening before the engine is even running. This will serve to baseline what's going on.

If you're still having problems after the above, it would also be helpful if you can post the exact codes that are showing up on the PIWIS when this problem occurs.

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