ECU tuning files: what they are and how FILHEX delivers them

What an ECU tuning File is

When a tool "reads" an engine control unit it does not produce a report — it copies the ECU's flash memory into a binary image, usually saved as .bin or in the tool's own container. That image holds the calibration: fuel quantity and timing tables, rail-pressure and boost targets, torque limiters, the models the ECU uses to manage the particulate filter, EGR and SCR systems, the diagnostic logic that raises fault codes, and the integrity data the ECU checks before it will run. In the trade this image is a "map", a "file", a "dump" or a "remap"; in FILHEX it is simply a File.

A tuning File is that same binary with specific regions changed for a purpose. A Stage 1 changes the performance tables within the limits of stock hardware. A DPF Removal changes the filter models, regeneration logic and related fault codes so the ECU stops managing a filter that is no longer in play. Nothing else in the File should change. That is why a good tuning File starts from a good original.

Original File and result File

Two Files matter on every job. The original (the "ori", "org" or stock File) is the untouched read of the ECU as it came into your workshop. The result File (the "mod") is what you write back. Keep the original with the job record forever: it is the only reliable way back if the customer changes their mind, sells the car, or the vehicle develops an unrelated fault that a dealer blames on the tune.

FILHEX keeps both on the same Solution Job: the original you uploaded, the Solutions you selected, and the result File with its download integrity check, so you can reopen any job later and see exactly what was delivered. If the car was already tuned by someone else, scan will usually report that fewer Solutions apply — the Catalog describes stock software, and a modified File is not stock. In that case the honest answer is to obtain a proper original for that software version before promising the customer anything.

How a File is read and written

The File reaches your laptop in one of three ways, and the route matters because the result must go back the same way:

• OBD — through the diagnostic socket. Fastest and lowest risk, where most everyday jobs are done. Some ECUs give a full read over OBD, others only the calibration area.
• Bench — the ECU out of the car, wired on the desk. Needed for a full read of many newer or locked units, and for recovery.
• Boot — the case opened and the processor accessed directly. For the units nothing else reaches, and for repairs after a failed write.

Upload the complete, unmodified read your tool saved. A partial read, or a File that was exported in a modified form, is the most common reason a scan lists fewer Solutions than expected. Virtual reads — an original pulled from a server by software number because the ECU cannot be read — can be uploaded like any other File, but confirm the car's actual software first: a previously tuned car with a mismatched virtual read is the classic way to brick an ECU on the write.

Write the result with the same tool and the same route you used to read, with a battery support unit on the car. FILHEX delivers the File; the read, the write and the decision to flash stay with your workshop.

What each Solution changes in the File

Solution	What changes in the File	Also searched as
DPF Removal	Soot and ash models, regeneration requests and post-injection, differential-pressure and temperature monitoring, related fault codes.	DPF off, DPF delete, FAP off
EGR Removal	EGR duty and flow set closed, position and adaptation handling, air-mass and torque paths that assumed recirculated gas, related fault codes.	EGR off, EGR delete, AGR off
AdBlue / SCR Removal	Urea dosing strategy, NOx-sensor feedback, SCR fault logic, countdown and no-start triggers.	AdBlue off, SCR delete, NOx off
Stage 1	Boost or VGT targets, injection quantity and timing, ignition advance on petrol, torque and limiter paths — within stock hardware limits.	Remap, chip tuning, ECU tuning
DTC clear	Selected diagnostic trouble codes switched off in the File so they do not return — for hardware that is no longer fitted, not for live faults.	DTC off, fault code delete

The full list — GPF / OPF Removal, swirl-flap and throttle-valve work, Start & Stop Disable, speed-limiter removal, TCU calibrations and more — is on the Solution list; what applies to a specific File is decided by scan.

Hardware and software numbers

Most file services ask you to type the ECU's hardware and software numbers before they can quote. FILHEX reads them from the binary: scan identifies the Brand and the ECU from the File itself and lists the Solutions published for that software. You can still confirm the Brand and ECU in the app, but you no longer depend on reading a label through an engine bay. The catalog shows published coverage by Brand, ECU and Solution before you install anything.

Checking a File before it goes on a car

The FILHEX Windows app ships a Hex Editor built for verification: open the original and the result of a job side by side, step through every differing block, read values as 8-, 16- or 32-bit numbers or as a graph, and search for bytes or text. It takes a minute to confirm that a Stage 1 changed the performance tables and nothing in the immobiliser area. Local byte edits are possible but stay on your PC; FILHEX does not correct checksums on Files you edit locally and warns you before you export one.

How you pay for tuning Files on FILHEX

1 Credit = 1 processed File. Each new Workspace receives 5 free Credits after email verification. Credit packs are €5 for 1 Credit, €40 for 10 Credits, €150 for 50 Credits, €200 for 100 Credits, bought in the Windows app, and never expire. A failed job returns its Credit, and DTC clear on a completed result File is free up to 3 times. Details on pricing; the service model on tuning file service.

FAQ

Background reading: what is an ECU File · how File scan confirms Solutions · starting an ECU tuning business · FILHEX blog.