SID305 Virgin File: Resetting the Immobilizer Pairing on Renault, Dacia and Nissan 1.5 dCi

The Continental SID305 controls the 1.5 dCi K9K engine in the Renault Clio III/IV, Megane III, Kangoo, Dacia Logan, Sandero and Duster, and in Nissan Qashqai, Juke and Note. Used SID305 units are cheap and plentiful, which is why the most common question we get is: “I fitted a second-hand ECU, the car cranks but will not start — what do I need?” The answer is usually a virgin file.

Virgin vs immo off

A virgin file is the original software with the immobilizer memory cleared, exactly as the ECU left the factory. When you write it, the ECU is unpaired and waits to learn the immobilizer code from the body computer (UCH on Renault/Dacia, BCM on Nissan). The car keeps its full anti-theft protection. An immo off file instead disables the check entirely: it is the right choice only when the body computer itself is dead or missing.

How the pairing works on the SID305

On Renault and Dacia the pairing is automatic: with a virgin ECU installed, switch the ignition on with a working key, wait a few seconds and the ECU stores the code from the UCH. On Nissan the BCM does not broadcast the code on its own; the ECU must be programmed with the NATS code using Consult or an equivalent tool, or you use an immo off file. Check which platform you are on before buying.

Reading the ECU

The SID305 is a TriCore ECU and is fully supported over OBD by KESS V2 and Flex; bench and boot mode work with KTAG when the OBD path is blocked (for example after a failed write). Reading takes 3–5 minutes. Save the original file — it is your only way back and the reference for matching the software number.

Choosing the right virgin file

• Match the hardware number (S180xxxxxx or 5WYxxxxx printed on the label) and the software number (237xxxxxxR on Renault, 23710-xxxxx on Nissan).
• A virgin file must be the same software version as the ECU, otherwise injector coding and DPF parameters may not match the car.
• If the ECU comes from a car with a different engine variant (75/85/90/110 hp) you also need an original file for your variant, not only a virgin file.

Writing and pairing step by step

1. Power the car with a charger; write the virgin file over OBD or on the bench.
2. Refit the ECU, plug all connectors, switch the ignition on for 10 seconds with the original key.
3. Renault/Dacia: the immobilizer light goes out and the engine starts. Nissan: program the NATS code with Consult, then start.
4. Clear stored faults and check for P0513/P1614 type immobilizer codes — they should not return.

Typical mistakes

• Writing a virgin file to an ECU that was never paired to the wrong car (nothing changes — the fault is elsewhere, often the UCH or the key coil).
• Mixing Renault and Nissan software: the hardware is identical, the immobilizer logic is not.
• Skipping the checksum step on tools that do not correct it automatically.

Getting the right file

See our virgin files for Renault, Dacia and Nissan and search the SID305 hardware or software number from your label. Not listed? Upload the original read on the file request page and we prepare the virgin version for the same day.