
$68.50USD
BMW Performance / MS42 Tuning
Fits: E36 · E46 · E39 · Z3
This is a custom binary flash for the Siemens MS42 ECU that permanently removes the EWS (Elektronische Wegfahrsperre) immobilizer loop from the DME. The ECU will start and run any M52TU engine without needing a matched EWS module, ring antenna, or key transponder.
Common use cases include standalone/swap builds, EWS module failure, damaged or lost keys, and track cars where a matching EWS system is impractical. All other ECU calibrations — fueling, ignition timing, VANOS, and emissions — remain stock and unmodified unless otherwise specified.
| Engine | BMW M52TUB25 / M52TUB28 |
| ECU | Siemens MS42 only |
| Market | US / Canada spec |
| Chassis | E36, E46, E39, Z3 |
| Displacement variants | 2.5L — M52TUB25 | 2.8L — M52TUB28 |
.bin flash file matched to your ECU hardware number (HW #) and software number (SW #).bin file via email — typically within 1 business day
MS42 is used exclusively on the M52TU engine — the M52TUB25 (E46 323i, E39 523i, Z3 2.5) and M52TUB28 (E46 328i, E39 528i, Z3 2.8). If you're unsure whether your car runs an MS42, verify via INPA or check the ECU part number — MS42 part numbers begin with 7 526 xxx or 7 527 xxx.
Note: The M54 engine uses the MS43 ECU, not MS42. Do not order this file for an M54 application — see our MS43 EWS delete listing instead.
This listing also supports a mail-in flashing service for customers who don't have access to flashing hardware. Ship us your ECU, we flash it and ship it back — typically a 2–3 business day turnaround from the day we receive it.
| Turnaround time | 2–3 business days from receipt |
| Return shipping | Included — USPS Priority Mail with tracking |
| Inbound shipping | Customer's responsibility — insure your ECU, they are not cheap |
| Accepted carriers | USPS, UPS, FedEx — no preference |
Packing tip: Remove the ECU from the car before shipping. Wrap it in bubble wrap and place it in a rigid box with padding on all sides. Do not ship in a plastic bag or padded envelope — ECUs have fragile connector pins.
Off-road / motorsport use only. This file is intended for vehicles not operated on public roads, including track cars, engine swap builds, and motorsport applications. Buyer is responsible for verifying compliance with all applicable local regulations before use.
This is a digital product — no returns or refunds once the file has been delivered. Have a question before purchasing? Contact us.