Renault Megane II and Scenic II Sagem S3000 Virgin vs Immo Off: Which File to Order

A Megane II 1.6 16v comes in with a replacement engine ECU fitted from a breaker. It cranks, doesn’t fire, and CLIP shows the immobiliser status as not programmed, or the red key light stays on. The ECU is a Sagem S3000 with 8200298457 on the label. This is the classic Renault second-hand ECU problem and the fix is a file, but it matters which one.

Two files, two different jobs

Virgin

A virgin S3000 dump is the ECU as it left the factory: no UCH code stored. On most Megane II and Scenic II, the ECU learns the immobiliser code from the UCH by itself at the first ignition-on with a matching key. There’s no key-programming procedure inside the engine ECU. CLIP is used afterwards to confirm the status, clear the fault memory and, if the customer’s keys were replaced, to program the keys into the UCH (not the ECU). So virgin is the right choice when the UCH is healthy, the keys are good, and you’ve swapped the engine ECU.

Immo off

An immo off dump makes the ECU ignore the UCH entirely. It starts whether the UCH answers or not. You’d pick this when the UCH is dead or water damaged, when the customer has one key and no code card, or when the car is used off road. The key light on the dash may still behave oddly, because the UCH still thinks it’s in charge. Nothing in the engine ECU changes that.

Once immo off is on the car, the transponder does nothing. Say so to the owner and note it. Insurers in the EU take a dim view of a factory immobiliser that’s been switched off on a road car.

Cars with S3000

Sagem S3000 sits on Renault petrol engines from roughly 2002 to 2009: K4J 1.4 16v and K4M 1.6 16v in the Megane II, Scenic II and Grand Scenic, plus the F4R 2.0 16v in some Megane II and Laguna II. Renault also used a Valeo S3000 later; check the label, because a Valeo unit is a different dump.

Part numbers on the shelf

• RENAULT MEGANE SAGEM S3000 8200298457 8200198100 DUMP
• RENAULT SCENIC S3000 8200298457 8200263160 DUMP
• RENAULT MEGANE S3000 8200387138 8200252665 DUMP
• RENAULT SAGEM S3000 VIRGIN DUMP

Renault labels carry two 8200 numbers: hardware and software. Match both where you can. If only the hardware number matches, a virgin dump will usually still start the car, but the calibration may differ (gearbox, emissions, region), so an original read from your own unit is preferable.

Reading the S3000

Two routes, and it depends on what you already own.

1. OBD on K-line. KESS V2, Galletto and MPPS all handle S3000 through the diagnostic socket on most versions. It’s a full flash read, and the immobiliser data is inside that flash on the Sagem unit (there’s no separate EEPROM to chase). Keep the battery on a charger; a ten minute write on a low battery is where these go wrong.
2. Bench. KTAG, FoxFlash or KT200 with the S3000 harness. Useful when the ECU won’t talk over OBD, or when you want the file without the car present.

Save the read before you touch anything. If a write fails halfway you’ll want that file, and we can rebuild from it. The bricked ECU guide covers the recovery order.

Questions we get about this ECU

Does a virgin file need CLIP at all?

Usually not for the pairing itself. You need CLIP (or a good clone) if you have to program keys into the UCH, or if the UCH also came from a breaker and needs its own virgin treatment.

Can I use immo off and keep the key light off?

Not reliably. The UCH still drives the light. Live with it or fix the UCH.

Second-hand ECU, first ignition-on, still not starting?

The used ECU was already paired to its donor. It won’t re-learn. That’s exactly what the virgin file is for.

Order the virgin file or immo off version from the Sagem S3000 page, or send your read with both label numbers through the request form. The original vs virgin guide explains the difference once more if you want it in one place.