Detroit / Mercedes ACM & MCM checksum fix online
Rebuilds every checksum block in a Detroit or Mercedes ACM / MCM full read. Upload your file and it comes back ready to use, corrected automatically — the calibration content is never touched, only the integrity value.
Sending costs nothing. We confirm we have your file, run the job on our server and tell you whether we can do it. You decide about paying after that — and you get the same file with a correct checksum.
| Price | 100 credits ($100.00) |
| Accepted | .bin · .mpc |
| Max size | 8 MB |
| ECU families | ACM 2.1 · MCM 2.1 |
- The same file back with a correct checksum — content untouched
- A yes-or-no answer on your file before you pay anything
- Works from any machine, nothing to install or license
- Charged per file, only when it succeeds
- No copy of your file is kept, ever
| Cummins calibration | 100 cr |
| Calterm configuration | 100 cr |
| Siemens SID OLS280 | 100 cr |
| Bosch EDC17 / MED17 | 100 cr |
How it works
Four steps, and you find out whether it can be done before you pay anything. What you get back is the same file with a correct checksum.
Upload it here. We confirm on screen that it arrived, with its name and size. This costs nothing.
We run the whole job on our server and answer one question: can we do this file, yes or no. If the answer is no you are told why, and nothing is charged — ever.
Only if the answer was yes. The price is shown before you decide, you tick to accept the payment terms, and the credits come off your balance.
Straight away, in the browser. Your file is processed in memory and never written to our disks.
How you pay
This tool costs 100 credits per file. Credits are prepaid and one credit is one US dollar — 100 credits is $100.00, with no subscription, no monthly fee and no minimum order.
You buy credits with a card or a PayPal account on the credits page, in packs — the larger packs carry a bonus, so a shop doing several files a week pays less per file. Credits do not expire and every movement, spent or returned, is listed in your account. Before any payment goes through — buying credits, or spending them here — you tick a box to accept the payment terms, and they are shown in full at that moment rather than hidden behind a link.
If a job fails after you have paid, the credits go back to your balance automatically and a refund line appears in your history. You are never charged for a file you did not receive.
How Detroit / Mercedes ACM & MCM checksum correction works
In WinOLS this family is handled by the plug-in numbered OLS824 — TEMIC / Conti MCM and ACM. It covers the Detroit aftertreatment and motor control modules found on DD13, DD15 and DD16 engines, and the Mercedes equivalents on OM47x.
These files are not protected by a CRC at all. Each protected block must satisfy a sum: add up the 32-bit words in the covered regions, add the number of words and the checksum cell itself, and the total has to land on a fixed constant. Change one byte of data and the total drifts by exactly that much — which is why a hand edit is caught instantly.
The newer four-megabyte reads carry a table inside the file describing their own protected regions, so nothing has to be looked up. The older two-megabyte reads do not, and the constant depends on the software line — we identify it from a fingerprint of the program area, which a tune never touches. A file has several blocks, and one block's region list can sit inside another block's protected area, so the correction is applied repeatedly until every block agrees.
You get back a full read with every block correct, ready to write to the module.
Questions
A full ECU read. The file must be 2,228,224 or 4,259,840 bytes; anything else is refused before you are charged, because a partial read does not contain the regions the checksum covers.
The older reads need a known constant for their software line, and ours covers the lines we have seen. If yours is new to us the format check says so and charges nothing — send us a stock read of that module and we will add it, usually the same day.
Not yet. ACM 2.1 and the MCM families are covered and tested; ACM3 is a different arrangement and we would rather tell you that than take your money and hand back a file that does not flash.
No. Only the bytes that hold the checksum are rewritten. Every map, limiter and parameter is returned exactly as you sent it — the file comes back the same size, and if you send a file whose checksum is already correct you get back a file identical to the original, byte for byte.
No. The file is processed in memory and never written to disk. Nothing is stored, nothing is indexed, and the corrected file only exists in your browser once it comes back. Close the tab and it is gone.
The credits go back to your balance automatically and a refund line appears in your credit history. You are only ever charged for a file you actually received.
No. It runs on our server, so it works from a workshop laptop, a phone in the yard, or a machine that has never had tuning software on it. There is no licence, no dongle and nothing to keep alive.