1992 ECM/Sys flashes in speedo
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1992 ECM/Sys flashes in speedo - SOLVED (post 4)
I’m trying to repair a 1992 LT1 coupe that is bone stock.
Symptoms: occasionally the spot on the digi dash that normally reads out for whatever gauges or fuel mode is selected flashes SYS. If this happens while the car is running it can be driven to the destination and shut off. If this happens when the car is not running (meaning key to run then to start) the car will crank but never start. If I wait long enough the car will start and drive normally until the next occurrence of flashing SYS.
Codes: Modue 1 code 41 Module 9 code 72. Both codes indicate failed serial communications.
The battery was old so I changed it out with a new one. The radio is stock but I pulled the CTSY fuse as a test. Neither the new battery or the pulled fuse helped.
I ordered a remanufactured ECM and moved the memcal from the old to the new.
With the reman ECM installed, all the fans come on when the key is turned to run (this is not normal) and the car will crank but never start. There is no flashing SYS with the reman ECM installed.
Moving the memcal back to the original unit returns the car to the previously described symptoms (if it starts it will run if it flashes sys before it starts it will not start if it is running when sys starts to flash it will keep running until it is shut down with the ignition key.)
Any help would be appreciated.
Symptoms: occasionally the spot on the digi dash that normally reads out for whatever gauges or fuel mode is selected flashes SYS. If this happens while the car is running it can be driven to the destination and shut off. If this happens when the car is not running (meaning key to run then to start) the car will crank but never start. If I wait long enough the car will start and drive normally until the next occurrence of flashing SYS.
Codes: Modue 1 code 41 Module 9 code 72. Both codes indicate failed serial communications.
The battery was old so I changed it out with a new one. The radio is stock but I pulled the CTSY fuse as a test. Neither the new battery or the pulled fuse helped.
I ordered a remanufactured ECM and moved the memcal from the old to the new.
With the reman ECM installed, all the fans come on when the key is turned to run (this is not normal) and the car will crank but never start. There is no flashing SYS with the reman ECM installed.
Moving the memcal back to the original unit returns the car to the previously described symptoms (if it starts it will run if it flashes sys before it starts it will not start if it is running when sys starts to flash it will keep running until it is shut down with the ignition key.)
Any help would be appreciated.
Last edited by 94z07fx3; Sep 13, 2012 at 10:34 PM.
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http://forums.corvetteforum.com/1554993058-post25.html
http://www.digitalcorvettes.com/foru...5&postcount=17
http://forums.corvetteforum.com/c4-s...cm-or-ccm.html
Fan run with key on is indicative of memcal/ ECM problem
Thread Starter
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At the moment I can swap the memcal from original ECM to reman ECM and back. Original ECM fails intermittently as described in the OP. Reman ECM fails 100% as described in the OP. If I am understanding you correctly then I would rule out the memcal and suspect the replacement part is defective. If I'm not reading you correctly can you steer me on the right path?
Thank you again!!!
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Solution: Replace ECM with used f-body unit purchased off eBay.
Failed reman unit was a Cardone. Vendor gave me full refund and shipping for the failed reman.
I would be interested, someday, in converting this 92 to a 94's comp and SEFI.
Failed reman unit was a Cardone. Vendor gave me full refund and shipping for the failed reman.
I would be interested, someday, in converting this 92 to a 94's comp and SEFI.
