Author Topic: Analog input issue. ADC gauge voltages all read 80v also egt issue  (Read 4373 times)

Offline jdm ej1 95

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Anyone see this before? is the chip fried?

this is the first time trying to wire anything into the analog pins on my ecu. wiring shift cut and launch control.  these are both wired with relays switching to sensor ground(on pins with pullup)

when going into ADC raw. all 8 gauges are pegged at (what says)  "80v"
no change when i switch to ground. still stay at 80v.

ALSO my EGT has never worked. it too is pegged at Max temp(something like 18000deg)




Offline VEMS

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Re: Analog input issue. ADC gauge voltages all read 80v also egt issue
« Reply #1 on: April 08, 2015, 08:36:35 am »
Hello Jdm ej1 95,

Most likely your mcp3208 ADC chip is fried; but it that also means that you (or someone else) must have supplied 12v to one of the ADC inputs, it is very hard to break the chip any other way.
Before all else you need to search for the cause of this problem, perhaps some wiring is mistakingly attached to ADC channels on ec18 connector which has 12v on them ?

Spare chips are available through the webshop: https://shop.vems.hu/catalog/8channel-mcp3208-p-135.html
If you do not feel comfortable soldering this yourself its also possible to use the repair/upgrade service (take care lead time is quite long): https://shop.vems.hu/catalog/repair-upgrade-p-103.html

Best regards, Dave