FAQ
TL;DR: Fast-flashing immo light on a 1999 Renault Scenic 1.6 16V is commonly fixed by switching between the 2 immobilizer types; expert tip: "change from immo 1 to immo 2" using Renault Clip. [Elektroda, Pawel wawa, post #16970778]
Why it matters: This FAQ helps Renault Scenic owners troubleshoot no-start immobilizer faults and decide between IMMO mode switch, key reprogramming, or IMMO OFF.
Quick Facts
- Symptom set: fast-blinking immobilizer LED and crank-no-start on Scenic 1.6 16V (1999). [Elektroda, Mikroprocesor, post #16963898]
- Typical trigger: voltage drop; check battery health and clean/secure fuse holders. [Elektroda, Pawel wawa, post #16964138]
- Real-world measurement: 12.01 V at rest, 11.7 V with low beams on (engine off). [Elektroda, Mikroprocesor, post #16964193]
- Fix path: with Renault Clip, switch IMMO mode (1↔2) in the boot lock tab; no PIN needed. [Elektroda, Pawel wawa, post #16970778]
- UCH accepts both IMMO types; engine ECU in this case operates as type 2. [Elektroda, adam7009, post #16974440]
Why does the immo light flash rapidly and the Scenic won’t start?
A voltage drop disrupts immobilizer authorization, leaving the LED flashing and the engine inhibited. Keep the battery healthy and clean fuse holders. As one expert puts it, “The fault only occurs as a result of a voltage drop.” Address power first, then attempt authorization again. [Elektroda, Pawel wawa, post #16964138]
Is it worth switching from IMMO 1 to IMMO 2 instead of removing the immobilizer?
Yes. Many fix the issue by switching the immobilizer mode with Renault Clip. This preserves OEM security and avoids ECU surgery. If power stability is restored, recurrence risk drops. Use the Clip’s boot lock tab to change IMMO mode. [Elektroda, Pawel wawa, post #16970778]
Can I handle this with DDT2000, or do I need Renault Clip?
Use Renault Clip. Contributors report completing the procedure with Clip; DDT2000 support is uncertain in this case. If low supply caused the fault, correct power issues first, then perform the Clip operation. [Elektroda, Pawel wawa, post #16964062]
How do I do a quick, at-home triage before towing?
- Measure battery at rest; charge or replace if low.
- Clean and secure fuse holders and connections.
- Retest start and authorization, then proceed to Clip changes if needed.
These steps target the voltage-drop root cause. [Elektroda, Pawel wawa, post #16964138]
What battery readings point to trouble on this Scenic?
A reported case showed 12.01 V at rest and 11.7 V with dipped beams on, engine off. Such readings indicate weak reserve and can trigger immobilizer faults. Stabilize supply before reprogramming or mode changes. [Elektroda, Mikroprocesor, post #16964193]
Can Renault Clip disable the immobilizer completely?
No. Clip can switch modes or turn off the dash LED, but it does not perform a true IMMO OFF. IMMO OFF needs ECU programming or an emulator. Turning only the LED off does not restore start authorization. [Elektroda, sadek1979, post #16964801]
Will central locking still work if I reprogram the keys instead of IMMO OFF?
Yes. Reprogramming the keys with the proper PIN keeps the central locking functional and preserves the original configuration. This approach avoids bypassing factory security and retains convenience features. [Elektroda, Jurek220, post #16970741]
What’s the practical difference between IMMO 1 and IMMO 2 here?
They are ECU authorization modes; the engine controller operates in type 2 for this case, while the UCH can handle both 1 and 2. Selecting the matching mode restores correct handshake with the transponder. [Elektroda, adam7009, post #16974440]
What is an immobilizer emulator (EMU), and when would I use it?
An EMU is a small module that mimics valid immo authorization to the ECU. It’s used when you choose IMMO OFF or need a non-tow solution. With an EMU installed, you avoid pulling the car to the service for authorization. [Elektroda, Pawel wawa, post #16970778]
Does this 1.6 16V use the “gumiak” ECU, and does tapping it help?
No. Experienced members note the 1.6 16V doesn’t have the so‑called “gumiak,” so tapping tricks won’t apply. Focus on power integrity and correct authorization steps instead. [Elektroda, Jurek220, post #16970741]
If my alternator charges but the car still won’t authorize, what next?
Check resting voltage and load voltage. Weak batteries can pass charging checks yet sag under load, causing immo faults. Replace a weak battery and secure connections before reattempting authorization or Clip operations. [Elektroda, Pawel wawa, post #16964138]
Do I need a PIN code to switch IMMO mode with Clip?
No. Switching from IMMO 1 to IMMO 2 in the boot lock tab does not require PIN codes. Follow the Clip procedure carefully and confirm power stability during the session. [Elektroda, Pawel wawa, post #16970778]
Can an EMU help me avoid towing to a specialist?
Yes. With an emulator installed, you can bypass failed authorization and avoid towing for service-side pairing. This is useful when Clip access is not available on-site. [Elektroda, Pawel wawa, post #16970778]
Which ECU family is in the 1.6 16V Scenic—Syrius 32?
No. A contributor confirms Syrius 32 isn’t used here. Use the correct ECU assumptions when planning IMMO mode changes or ECU-side work. [Elektroda, Pawel wawa, post #16970778]
What tools are commonly mentioned for diagnosing this issue?
Renault Clip for IMMO mode changes, Delphi for code reads, and DDT2000 for parameter viewing. Owners often start with a scan to identify immo loop supply errors before deciding on Clip work or EMU. [Elektroda, Mikroprocesor, post #16963898]
Are transponder types relevant (wedge vs block)?
Yes. Owners discuss TP19 (“wedge”) and TP21 (“block”) and how UCH and ECU modes must align with the transponder type for successful authorization. Mismatches can prevent starts. [Elektroda, Mikroprocesor, post #16965341]
