IMMO OFF or VIRGIN – which engine ECU to choose?

IMMO OFF is an ECU with the immobiliser disabled that works once plugged in. VIRGIN is an ECU wiped to factory state – some learn the car by themselves, others must be programmed.

We explain the differences using the ECUs we prepare: Fiat, PSA, Audi, VW, Opel, Ford and BMW.

author: EcuSale
added: 02-11-2026
in category Guides: IMMO OFF, VIRGIN, programming , Engine ECUs

IMMO OFF or VIRGIN – what is the difference and which engine ECU to choose?

What does IMMO OFF mean?

Every time you start the car, the immobiliser checks that the key and the engine ECU recognise each other. A used ECU from another car fails this check and the engine will not start. In an IMMO OFF version the immobiliser function is disabled in the ECU software, so the engine starts without exchanging a code with the key.

For the driver this means fitting without programming: plug the ECU in and drive. With some ECUs the car then runs with no errors at all; with others an immobiliser message remains on the cluster or in diagnostics, although the engine runs normally. Details below.

What does VIRGIN mean?

A VIRGIN ECU is wiped back to a “blank” state: no VIN and no immobiliser data from the previous car. The immobiliser stays active, so the car keeps its factory anti-theft protection.

There are two kinds of VIRGIN ECUs. Some adapt themselves to the car and immobiliser the first time the ignition is switched on. Others have to be programmed with a diagnostic tool in the car.

Not sure which version to choose?

Send a photo of the old ECU label to sale@ecusale.com or via WhatsApp +48 888 638 546 (Mon–Fri 9–16). We will select the ECU by part number and tell you whether it will be IMMO OFF or VIRGIN.

VIRGIN that programs itself (Plug & Play)

After fitting and switching on the ignition, the ECU stores the car and immobiliser data by itself. No error remains. We prepare these this way:

Fiat and Lancia Magneti Marelli MJD ECUs, e.g. 1.3 Multijet,
Bosch ECUs for the Fiat Ducato 2.3,
Continental SID208 for the Boxer, Jumper and Ducato 2.2,
Magneti Marelli IAW for petrol engines.
Visteon for the Fiat Ducato, Peugeot Boxer and Citroën Jumper 2.2.

On request we can also prepare Fiat ECUs as IMMO OFF. In that case a red immobiliser light stays on and a fault code remains in diagnostics that cannot be cleared. That is why we recommend VIRGIN for Fiats.

IMMO OFF with no errors

These ECUs work once plugged in, with no programming and no messages on the cluster:

PSA (Peugeot, Citroën) Valeo J34P and Siemens SID801 families – Peugeot ECUs,
VW T4 and LT 2.5 TDI and Amarok 2.0 TDI – Volkswagen ECUs,
Audi Q7 3.0 TDI EDC16 family and Audi TT 1.8T (Bosch ME7.5) – Audi ECUs,
master + slave pairs for the Audi Q7 4.2 TDI,
Kia and Hyundai ECUs.

IMMO OFF with an immobiliser warning – the car starts and drives

With some ECUs the engine runs normally after IMMO OFF, but an immobiliser message remains on the cluster or in diagnostics:

Audi Q7 3.0 TDI EDC17 family – a cluster with the large display shows SAFE, the small one does not,
VW Touareg 3.0 TDI EDC17CP14 (7L0907401N, 7L0907401H),
Fiat ECUs in an IMMO OFF version ordered on request (red warning light),

If you want to get rid of the message on an Audi Q7 3.0 EDC17, a workshop can carry out an immobiliser adaptation.

VIRGIN for programming – Opel and Mercedes

We sell Opel ECUs as VIRGIN units that must be matched after fitting with a Tech-2 or OP-COM tool. You need the car’s PIN code or Car Pass. This applies, among others, to Opel ECUs 1.3 CDTI for the Corsa D, 1.7 CDTI Denso for the Astra H and Zafira B and 1.8 Z18XE, and to UEC modules (these come with a PIN code).

We prepare Mercedes ISM (gear selector module) units up to 2013 as VIRGIN. Programming has two stages: first the actuator is calibrated, then the ISM is adapted to the gearbox and the car.

Key or data programming – Ford, BMW, Audi Q7 4.2

Ford DCM3.5, ESU-411, ESU-412, ESU-312, EcoSport, Transit Connect and Ka need PATS programming (FORScan or IDS, with the keys and VIN). After purchase you can send us the VIN and we prepare the ECU with Ford server data at no extra cost. See Ford ECUs.
BMW DDE (Bosch) units need programming with ISTA/P or ISTA+, or cloning. See BMW ECUs.
Audi Q7 4.2 TDI – a single master or slave ECU must be programmed (ODIS, VCDS or VAS). We sell master + slave sets as IMMO OFF Plug & Play; these must not be updated at a workshop, because an update switches IMMO OFF off.

Where is the engine ECU fitted?

The mounting location matters, because it decides what the ECU is exposed to. In the cars we deal with most often:

Opel Corsa D 1.3 CDTI – under the scuttle. Water floods it when the drains are blocked or when snow lying on the scuttle melts.
Audi Q7 3.0 TDI and 4.2 TDI – in the scuttle area, where moisture collects when the drains are blocked. The Q7 4.2 TDI has two ECUs: the master mounted horizontally and the slave mounted vertically.
Fiat Ducato 2.3 Multijet – in the engine bay, close to the wheel and wheel arch, where water, salt and dirt get in.
Ford with DCM3.5 – in the engine bay, usually behind the front bumper, by the left wheel arch or under the headlamp.

If the ECU was flooded, remove the cause before fitting a new one: clear the drains, dry the mounting area and check the connector for corrosion. Otherwise the new ECU may fail in the same way.

Cloning – a third option

For many ECUs (including Opel, Fiat Ducato Bosch, Audi Q7, BMW and Mercedes ISM) we can also transfer the data from your old ECU or its files to the new one. The ECU then works like the original, with no programming in the car. Cloning is included in the ECU price.

Popular IMMO OFF and VIRGIN ECUs – part numbers

Below are the most searched ECU families with example product pages. You will find the full list of numbers in the brand categories.

Bosch – Fiat Ducato 2.3 Multijet (VIRGIN)

We prepare them as VIRGIN Plug & Play – after fitting they match themselves to the car and the immobiliser.

Magneti Marelli MJD 6F3 – Fiat 1.3 Multijet (VIRGIN)

We prepare them as VIRGIN Plug & Play – after fitting they match themselves to the car and the immobiliser.

Continental SID208 – Peugeot Boxer, Citroën Jumper 2.2 HDi (VIRGIN)

We prepare them as VIRGIN Plug & Play – after fitting they match themselves to the car and the immobiliser.

Visteon – Fiat Ducato, Peugeot Boxer, Citroën Jumper 2.2 (VIRGIN)

We prepare them as VIRGIN Plug & Play – after fitting they match themselves to the car and the immobiliser.