ECU not identified: open a ticket, or proceed anyway

This one comes with a choice built into it, which is why it needs more than a paragraph. The
tool has read something but cannot match it to a known original, so it is asking whether you want
it checked or whether you want to carry on regardless.

Why an ECU fails to identify

• It has been tuned before, so the file no longer matches any original on record
• The read is incomplete or corrupt, so there is nothing coherent to match
• It is a variant or software version that has not been catalogued yet
• It is not the ECU the vehicle left the factory with
• It was read with the wrong protocol or the wrong memory area

Only the first and third of those are harmless. The others mean the file in front of you is not
what you think it is.

What proceeding anyway actually means

It means going ahead on a file that the system could not verify. If the read is sound, that is
usually fine and the file just needs adding. If the read is not sound, you are about to modify
something incomplete and write it back into the ECU, which is how a running car becomes a
non runner.

The specific risks, in the order they bite:

• A partial or corrupt read written back. The ECU ends up holding software that
  was never complete. Usually a no start, sometimes a permanent recovery job.
• Tuning on top of an existing tune. If the file was already modified, changes
  get stacked on changes nobody has a record of, and the result is not what either party
  intended.
• Wrong identification. If the file is assumed to be one thing and is another,
  the assumptions about where things sit inside it are wrong too.

When proceeding is reasonable

• The read completed with no errors reported at any point
• The tool verified the checksum
• The file size is what you would expect for that ECU, and it is not full of blank or repeated
  data
• You have saved a verified original and can put it back
• The car came in running normally

When it is not

• The read errored, stalled or was interrupted at any point
• The file is obviously short, or reads as all FF or all 00
• The vehicle already has a running fault, or has been to someone else first
• You do not have a known good original saved
• You are working on someone else’s failed job

The honest answer

If you are asking yourself whether it is safe, open the ticket. The wait is minutes. A recovery
is a day and a difficult phone call to your customer. Nothing about proceeding anyway gets easier
by doing it faster.

What to attach to the ticket

• The log file from the session
• The read file or files, exactly as the tool saved them, not renamed or repacked
• The ECU hardware and software numbers, from the label or from a diagnostic read
• Registration or VIN, engine, and gearbox
• Which tool and which connection method you used
• What the customer has asked for, and anything already modified on the car

And before any of it: a proper battery support unit on the vehicle, not a trickle charger, and
a full original read saved somewhere you can find it again.