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Old 05-03-2007, 08:02 PM   #1
DoctorNick
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Default Voltage drop, flash errors out.

I have had two tuners try to flash my stock v7 ECU. One using ecutek the other using openecu. Both get thru the whole flash process but then error out at the last second. I have tried using a battery jump to keep the system at full voltage. no go. No matter what it drops down to under 4.3 volts.

I would imagine the next step is to go thru the wireing harness and look for melted wires, pulled out grounds and all that other fun stuff. What I was wondering though, would it be possible to artificially add 12 volts to the ecu? Would there be a pinout I could use to find the correct wires that require the voltage?

insight/similar experiences are apprecaited
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Old 05-04-2007, 01:30 AM   #2
Hyper
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join the club!

same thing, JDM swap, same 4.3V error

answer to that - yes, you can jump 12V and then turn headlights/AC to bring the voltate to 12V because it can be a little more

questions is - TO WHICH WIRE!?

I went there few days ago with a voltmeter, and none of those OBD wires showed me 4.3V

only variation in voltage I saw was pin 9

this is what I observed:

test connectors disconnected/connected - 5V
test connectors disconnected/connected WITH openport cable connected to laptop - 9V (9.1~9.3V was jumping when I switched lights/AC)

However my old ECU was ECUTEKed lot of times, and it was ok - it gave problems sometimes, but when we wiggled the wire in the port it worked
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Old 05-04-2007, 02:59 AM   #3
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hyper, who did your swap I find this to be MUCH too coincidental
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Old 05-04-2007, 09:17 AM   #4
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I was getting 3.4 - 3.9 volts also. (not a swap though) Turned out to be a bad tactrix cable. Emailed them, and they sent out a new cable the next day (with a prepaid envelope to return my old one.) new one works great!
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Old 05-04-2007, 11:11 AM   #5
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I was getting a USB port overload on my laptop, my heatshrink came off inside the tactrix cable causing the shield to touch the circuit board. Cut open the housing & retaped the shield up, no more problem. Could be a similar issue but if the ECUTek tuner is doing the same thing w/ a different cable then thats not it.
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Old 05-04-2007, 11:54 AM   #6
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Good suggestion, I have tried a ecutek cable and 2 tactrix cables though. Gonna bribe a friend into helping me go thru the wireing diagram. See if we can artifically give it 12 volts. Pictures and write up on the way if it works.
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Old 05-04-2007, 12:06 PM   #7
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did you disconnect the fans?
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Old 05-04-2007, 12:16 PM   #8
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Quote:
Originally Posted by Jaxx View Post
did you disconnect the fans?
interesting, but the fans don't cycle during flashing, just in the "diag mode" right?
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Old 05-04-2007, 12:48 PM   #9
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Quote:
Originally Posted by HndaTch627 View Post
hyper, who did your swap I find this to be MUCH too coincidental
VerIII on the boards, he really did a great job!
and as it appears, it's a common problem

and yes, fans don't cycle when the program is reading/flashing

oh, here's another thing - I have no problems reading the rom!
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Old 05-04-2007, 01:21 PM   #10
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I can read the rom too, I can start to burn the rom and it errors out. That the only problem I have. I am gonna go out and start pokin wires now. hopefully I don't fry the ecu
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Old 05-04-2007, 03:15 PM   #11
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Alright, tapped #1. 12 volts right off the battery. I used my running FXT to juice the battery to insure I had the correct voltage. Still nothing. 4.28/4.3
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Old 05-04-2007, 03:19 PM   #12
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check them all with voltmeter after you connect test connectors and have your lapton ON with the cable in OBD

most of them were already 12V in my case, with only one variation in #9

also, see if you have anything on pin #6

ok, now get back to it!
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Old 05-04-2007, 03:29 PM   #13
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something else I just thought of...... while you're at it, check the voltage on the following pins:


ECU A10 and A14 (I assume you have V7+)

when flashing, A14 should be grounded.... I am curious as to what A10 will give you

also try A20, it also goes to datalink connector

report
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Old 05-04-2007, 03:53 PM   #14
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Yeah, its a v7 swap. I don't have a voltmeter, gonna go to autozone and buy one

Can you point out what pages in the wireing diagram your looking at?
I'll report back in the next few hours. I have actual work to do at...work
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Old 05-04-2007, 05:18 PM   #15
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I am at a lecture right now, so I don't have the file... but the info I posted about doesn't come from the diagrams, it comes from swap experience of someone
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Old 05-05-2007, 03:08 AM   #16
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Quote:
Originally Posted by Hyper View Post
I am at a lecture right now, so I don't have the file... but the info I posted about doesn't come from the diagrams, it comes from swap experience of someone
oh, don't go giving neal instructions like that, he'll end up really frying his ECU. I'll go thru it this weekend and see what we got.


At least this isn't a one off problem.
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Old 05-05-2007, 05:13 PM   #17
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"re-wired" my gauge/radar mess. Since I assumed my defis were eating some voltage (my oil pressure warning goes off when the car is turned on). Well no improvements. I'll start following wires tomarrow
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Old 05-06-2007, 09:55 PM   #18
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well where do i start with this. Spent some time today on this problem and the results were completely unexpected. What was found was that between the last shop that successfully flashed the ECU in the car and the next shop that touched it for tuning someone decided to cut off the flash block connector or intentionally severed the harness between A10(white/red wire) and the DLC pin 6. I repaired the broken wire and the ECU Flashed just as it was meant to. I'm actually really stumped about this whole thing because I can't picture anyone doing this intentionally but it's almost impossible that it wasn't done intentionally since the harness was taped shut with that wire inside the harness.

*shrug*

oh well, i guess it's just kinda sad that none of the 3 shops who attempted to flash the ECU previously were able to diagnose something so simple.

Jeremy
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Old 05-07-2007, 12:30 AM   #19
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Quote:
Originally Posted by HndaTch627 View Post
I can't picture anyone doing this intentionally but it's almost impossible that it wasn't done intentionally since the harness was taped shut with that wire inside the harness.

*shrug*
+1 to the shrug.

Thanks again hondaboy.

My car is flashable again. wooooooooo
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Old 05-07-2007, 12:39 AM   #20
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ok, stop browsing clasifieds and say how?????
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Old 05-07-2007, 12:47 AM   #21
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Whatcha mean how, basically this one wire was connected to the OBD-2 but was severed about a foot up the harness. So unfortunally my advice to you is gonna be start tracing wires
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Old 05-07-2007, 12:50 AM   #22
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which pin was it?
also do you have a flash connector, or it's integrated into the harness? (my case)

if I understand correctly, this mystery wire has to go to one of the pins of ECU providing it with 12V of voltage for flashing, so if I knew which one it was it would be easier to check it on ECU side
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Old 05-07-2007, 01:01 AM   #23
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Quote:
Originally Posted by Hyper View Post
which pin was it?
also do you have a flash connector, or it's integrated into the harness? (my case)

if I understand correctly, this mystery wire has to go to one of the pins of ECU providing it with 12V of voltage for flashing, so if I knew which one it was it would be easier to check it on ECU side
no no no, Pin 1 in the DLC is constant power and the ONLY pin that is provided power. DLC Pin 6 goes to the flash memory connector(which has been omitted on this vehicle and wired directly between the ECM and DLC...DLC pin 6 to ECM Pin A10), DLC Pin 8 goes directly to the ECM Pin A20, DLC Pin 10 goes to a splice then direction to ECM Pin A21, DLC Pin's 12 & 13 Go directly to body ground.

Does that clear things up? Don't worry about transmission voltages, worry about resistance in the harness. It's the easiest way to find an open/short.

Jeremy
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Old 05-07-2007, 01:11 AM   #24
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^ my eyes kinda glaze over and brain shuts off when he starts talking like that
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Old 05-07-2007, 01:29 AM   #25
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I went through too many diagrams troubleshooting my AVCS, so I already understand this language

Jeremy, I tend to believe this is how the car is wired because it was flashing fine with ECUTEK, but I will go throught it again

thing is that I don't remember if we retained all pins in the DLC from 99RS when we swapped it, because two harnesses were merged.... I don't even think I have pin 6 in the DLC (I look at the marked numbers on the back side of it)... besides, I don't think there is a pin in the openport cable that corresponds to pin 6 in DLC

what is the allowable resistance, and if that's the case I will still have to jump 12v onto that wire so why not fix it on the ECU side? I just don't know which pin is responsible for that
also is resistance costant on both ends of the wire? (DLC vs ECU) I am not very skilled with electrical stuff which is why I wasn't wiring the car

a lot of WRX people also had this problem, and jumping additional 12v seemed to solve it




maaaan, I hate swaps!
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