How do you reference the numeric and alphabetic white sticker on the ECM? Is the SERV NO the part number? Are all GM compatible using the same engine? Example 1993 SERV.NO-16159278 with three additional group of letters and numbers
C4 ecm
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Re: C4 ecm
The service number (left top of label) is the part number for the ECM for that year. The 4 letters on the top right is the BCC (Broadcast code) which is the chip (eprom) inside which holds the program setting for your car. From the BCC you can tell the engine, transmission and rear gear ratio that it is programmed for.- Top
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Re: C4 ecm
For the most part yes although the ECM itself is used in other GM cars under a different service number. The chip (eprom) is specific to the car and should match. Now the chip is removable and can be placed into another ECM. Most problems are with the circuit board in the ECM and not the chip itself.- Top
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Re: C4 ecm
Heat and vibration can be factor in circuit board issues.
The 93 was the last year for the black box style ECM with a prom chip. The same ECM was used in 93 camaro z28.- Top
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Re: C4 ecm
The prom is factory but there are businesses that will burn a new prom for your car. You can usually find them on sites like eBay or any number of corvette part sites. What is the 4 letter BCC on your ECM?- Top
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Re: C4 ecm
First of all i am troublshooting a closed loop prblem that comes and goes. Second i am buying spare parts because of the shortage of NOS. Third i bought this car new and want all the education on these C4 i can gather! This car is a keeper!- Top
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Re: C4 ecm
The 92 and 93 C4 used the same ECM (16159278) and proms. The is basically 4 proms for the LT1 one for the 6 speed and 3 for automatics with different rear gear ratios. Most sellers on eBay ask way to much for used ECM but every so often there are good deals. I picked up one this past summer on eBay for my 90 for less than $60.
I've attached an article I found on the internet on proms that you may find interesting.Attached Files- Top
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Re: C4 ecm
The second line is the bar code. The BAFL in the bar code will be to the top right of the label. The BAFL is the BCC of the prom that is for a LT1 with 6 speed manual transmission and a rear gear ratio of 3.45. If you were to look at the prom it should have part #16173866.
I spent some time researching the ECM for my 90 when I was getting it ready for flight judging. My car had a re-manufacturer ECM when i got it and I wanted to find the correct ECM label since it was listed in the JM. Over time it kind of became an obsession of mine LOL.- Top
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Re: C4 ecm
that is correct! Now I would like to find a scan tool for this OB1 set up. I can pull codes with a paper clip by jumping out two pins or just by using my old code scanner but with this type of distributor and computer I need all the help I can get.- Top
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