A serial memory has rules for writing groups of bytes. Crossing a page boundary incorrectly can place data somewhere other than the intended location, even when the electrical connection is sound.

How to narrow it down

Identify the exact device and its page organisation before assessing a failed write. Compare the original file, intended write and verified read-back by address. A pattern repeated at regular boundaries can point towards the programming method rather than random memory damage.

What to include with the fault report

Keep the untouched original file, device marking and full programming log.

Page size is not universal across EEPROM families. Data recovery should preserve the original before any further write attempts.

Speak to AXION

For module programming and coding support, send your vehicle details and fault report. Workshop assessment is in Didcot, Oxfordshire. Suitable postal or remote work is confirmed before booking.

Technical background from Microchip. The referenced design explains the principle; the vehicle-specific procedure determines the repair.

Related reading — An EEPROM temporarily not acknowledging after a write. Browse all vehicle-electronics diagnostic notes or return to the repair library.