hypertech obd1 code 51

[scuddigi_687@yahoo]

hello again my 93 chevy caprice has a 5.7 engine out of a 1ton van my buddy sold me his hypertech chip which i easily put into my ecm now my car runs strong and beee-aaaaa-uuutiful but my check engine light flashes rapidly ND WIHLE PERFORMING THE EASY CHECK ENGINE LIGHT I pulled code 51 does anyone know how to erase that and still maintain my new found power I will post the part number later tonight THANKS!

[Blue Bowtie]

51 is a PROM checksum error. The broadcast code for the PROM must be the same (or compatible with) the ECM and firmware.

You can clear the code by disconnecting the battery but it will likely return.

[scuddigi_687@yahoo]

Originally Posted by Blue Bowtie

51 is a PROM checksum error. The broadcast code for the PROM must be the same (or compatible with) the ECM and firmware.

You can clear the code by disconnecting the battery but it will likely return.

OKAY what is a broadcast code and I did the battery thing but you are right it came back.

[Blt2Lst]

Try putting the stock chip back in, clearing the codes, and see if that corrects the problem.
Maybe the chip is bad.

[Blue Bowtie]

Within the structure of the binary program help on the PROM is an identifier for the program, also known as a broadcast code. It us usually half of a hex word of programming.

Another memory word is the product of the length of the program and the number of binary "1"s in the program (the checksum). This is done to make sure the program doesn't get corrupted somehow and that it is reliable. If the number in the program code doesn't match the number calculated when the ECM powers up and performs its tests, the error code will set. This can occur from a voltage spike, poorly connected PROM, incorrectly programmed PROM, or damaged PROM. It can also occur if the PROM is inserted into an ECM that uses a different format for memory locations and layout (mask) causing the ECM to read the PROM incorrectly. Because of this, the broadcast code must be compatible with the ECM.

You may be able to diagnose the problem by connecting your computer and reading the data and PROM information. It's something like this:

http://www.youtube.com/watch?v=hQ5d4ia8ubQ

You can also read the PROM and study the code in binary format to make sure it's compatible, and also CHANGE the parameters for what you want. That's the fun and rewarding part. I've been doing that for a decade or so on several different families of ECM/PCM and fuel systems.