mjrav Posted October 1, 2011 Share Posted October 1, 2011 Any help with this is greatly appreciated. The check engine light has been on for some months with a code of P0601. "Internal control module memory check sum error" The car could not be running any better. The light is the only issue. I reset the check engine light three times and it comes back on in `12 to 80 miles. Is the ECM necessarily bad and needs replacing or is there some other option. Where in the car is the ECM? In the passenger seat back? Thanks, Mark Quote Link to comment Share on other sites More sharing options...
flaco Posted October 1, 2011 Share Posted October 1, 2011 When a computer processor first powers up, it does a checksum calculation. It is a mathematical calculation on al the bits and bytes in the memory. If all is well it comes up with a specific sum (checksum) which is compared with a checksum stored in memory. If they don't match, you get this error. Somewhere, the memory has a wrong bit. It is just an annoying thing and in the end your car can't pass inspection even though there is nothing wrong with it. Only fix is to replace that ECM. I don't know where it is, hope someone else can tell you. I'm a retired electronics engineer, not a car mechanic. Quote Link to comment Share on other sites More sharing options...
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