King ecu connection ecu

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Lpg08
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King ecu connection ecu

#1 Post by Lpg08 » Wed Apr 29, 2020 4:06 am

Hi guys having issues with connection between my laptop and ecu.

Problem i have is that ecu connects fine but whist driving it will disconect and when you try to reconnect it will give a c01 error code.
Restarting the computer does not help. Onoy thing that helps is removing the lpg ecu fuse and then reconnecting where it will work until a few minutes and disconnect again.

I measured the tx and rx pins on the ecu and when theres no connection fault both pins are 5volts when it disconnects on of the pins (not sure tx or rx) drops to 2.5volts even with cable disconnected.

Once you remove the ecu fuse and replug it goes back to 5v until it repeat.

To me it sounds like a ecu issue but in not sire what in the ecu controls the tx rx communication so cant check anything yet.

Hope someone knows a fix for this issue.

Thanks

Gilbertd
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Re: King ecu connection ecu

#2 Post by Gilbertd » Wed Apr 29, 2020 10:10 am

What are you using to connect, USB or serial, has it ever worked and if it has, what changes have you made (updating Windoze, etc)?
96 Saab 900XS, AEB Leo, sold
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Brian_H
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Re: King ecu connection ecu

#3 Post by Brian_H » Wed Apr 29, 2020 10:32 am

I'd think its more likely an issue with the power to the ecu, either corrosion on the loom somewhere, or a bad connection to the battery itself. The inline fuse holders can be problematic (get damp inside and start corroding, though you'd have seen that with what you've done already, or the contacts lose their spring effect and don't grip the fuse so well, can help to remove the fuse and gently squeeze the holder with pliers if its the rubber type one, or to change the fuse itself for a better quality one - some of the cheap aftermarket ones don't have particually thick pins compared to original ones).

Its also possible that you need to look at the earth side of the ecu connection as well, That may be connected directly to the battery post like the positive one, I've had all sorts of errors appear when the battery connection gets bad enough, a cleaning with a wirebrush to the post and connector was enough to sort those out.

Can also be worth taking the connector off the ecu and making sure there isn't signs of corrosion in there (should be watertight if its been assembled properly, but worth ruling out).

If its a metal cased ecu, is it bolted to a good ground point as well? Battery well charged?

Has the install ever worked, or is this a new install your trying to get working?

LPGC
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Re: King ecu connection ecu

#4 Post by LPGC » Wed Apr 29, 2020 11:33 am

Even with good power connections and on new installs I've found it's sometimes necessary to remove and refit the main fuse with some types of connection problems with recent spec AEB2568's.
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Lpg08
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Re: King ecu connection ecu

#5 Post by Lpg08 » Wed Apr 29, 2020 1:27 pm

So there is abit more to the story that i havnt mentioned.

Firstly if had this system running for a while and i have always had issues with connection to the ecu.
I believe my issues were with my cable as during tuning the signal would drop out but i was able to always reconnect without reseting the ecu.

So i got a new cable but never tried it vefore this issue.

So the part that i didnt mention earlier is that during another lpg install on another vehicle i was measuring the tx and rx pin voltage on me king ecu as just a comparison (diagnosis) and i screwed up by leaving the multi meter on continuoty test mode and when i went to check the rx pin it shorted between the negative side of the voltage.

I straight away put the multimeter to volt mode and measured the voltage and in droped to 2.5volts where as tx line was 5v i thought i had blown the ecu. But car still ran fine

So i turned the ignition of then on again and rx went up to 5v again and everything was fine until i tried connecting the laptop a few days later to touch up the tune.(connected fine for 5 mins then disconnects and needs ecu reset to function again, also seems to only disconnect whilst drivong if left connected with engine at idle seems not to have this issue)

So know i dont know what shorting the rx pin to ground did to it where it functions fine until a certain time then drops to 2.5volts and needs the ecu to be reset ti function again for a short time.

I assume this problem has risin due to my stuff up but im having a hard time understanding what i damaged that causes it tonwork but for only a short period of time.

Hope this is repairable.

LPGC
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Re: King ecu connection ecu

#6 Post by LPGC » Wed Apr 29, 2020 1:36 pm

Is this the order of events...
You had problems connecting with the other cable
You then accidentally shorted a couple of pins in the LPG ECU's interface plug
You then bought another cable
The new cable has the same problems as the old cable
Both cables will connect but randomly lose connection when running on LPG
?
Full time LPG installer
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2 miles A1, 8 miles M62,
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Lpg08
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Re: King ecu connection ecu

#7 Post by Lpg08 » Wed Apr 29, 2020 1:47 pm

Initial cable had issue with loosing connection but guessing tx and rx were not dropping to 2.5v hence could reconnect by ctrl c

Shorted pin on ecu voltage on one pin dropped to 2.5v tried connecting to pc with old cable but error c01 until i reset lpg ecu and voltage came back to 5v (did not use old cable long enough to see if it drops to 2.5 volts)

Got new cable and connects fine as did old cable but rx line drops to 2.5 volts aftwr 5ish mins

So they are both connection issues before and after but in differerent ways.

My new cable work fine on another lpg vehicle so the cable should be fine.
The original cable had issues on the second car aswell hence why i got a new one.

Gilbertd
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Re: King ecu connection ecu

#8 Post by Gilbertd » Wed Apr 29, 2020 4:12 pm

Why are you measuring voltages on a data line? It will show 5V when no data is being transferred and 2.5V when it is as the voltage will be being turned on and off. If you want to check you need a scope on it to see the data pulses, a meter will tell you nothing.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


Proud member of the YCHJCYA2PDTHFH club.

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