Before you ask — check these 5 things first

Most failed jobs are answered by these questions. Please check them before starting immo off or contacting support:

1. Is the car's ORIGINAL ECU and the USED (donor) ECU exactly the same? Same label, same SW number, same CODING?
2. Was ECU cloning tried before (original → used ECU)? Did anyone work on this ECU before you? Ask the customer for the full history.
3. Is this a LOST-KEY problem or an ECU-REPLACEMENT job? Immo off does not add or program keys.
4. Which flasher are you using — and did you run the CHECKSUM? Write with the same flasher you read with, and always do checksum.
5. Is the key matched to the car? Or is there a KEY / FEM / TCU / BCM problem?

New ECUs cannot be cloned 1:1 — and why immo off can fail

When OtoCheck performs immo off, it uses the ECU's ORIGINAL MCU ID serial number and also its ORIGINAL password. If such an operation (clone, wrong immo off, file editing) was already done on this ECU before, immo off will not work.

On new-type ECUs, immo off is ONLY for ECU REPLACEMENT — not for lost key, all-keys-lost, etc.

Car does not start (or windows don't work) after immo off?

If the vehicle does not start, or the windows / comfort functions do not work after immo off, then the KEY and the DASH (or BCM) are not matched. The key must be coded / synchronised to the BCM or dashboard — otherwise the windows will not work.

Known flasher bugs

KESS3 and TRASDATA have many bugs (PCR 2.1 different format, bad MCU ID and some others).

FLEX bug in Simos 6, 8, 10, 11, 12, 16, 18.xx checksum.

ALL other flashers found bad MCU ID — you can check your MCU ID in our MCU ID detector: www.otocheck.com/online/mcuid.php

Autotuner reading split files + checksum problems.

Why does IMMO OFF not work?

FIRST BE SURE you have an IMMO problem or any external problem like fuel pump, injectors or RPM sensor. You can check live data (RPM sensor and others) in diag tools.

Please listen to the car's error history and understand the problem. If the car stopped during the road it is not an immo problem. Immo never cuts a working engine — immo is only for starting the car.

You can compare the files you read and write to understand how your flasher reads them and use them with other devices. But the general rule is: write with whatever flasher you read with, and always do Checksum.

1. The original ECU and the ECU to be used must be 100% the same. You can understand this by comparing the label picture of the ECU. The HW number is the hardware number, the SW number is the software version. If these are the same but it still does not work, CODING must be checked. In VAG you can convert the ECU with the frf/sgo method after immo off. Other brands are sometimes possible with dealer REPROGRAMMING methods using current car VIN info. BUT THE MAIN RULE: ECU HW numbers MUST BE 100% SAME.
2. If the programs in the ECU have been tampered with before (clone or incorrect immo off), or if there was a break while programming, immo off will not work. PLEASE ASK THE CUSTOMER FOR ECU HISTORY (from other shops too).
3. Key and Dash or BCM or EZS must match in newer cars to CRANK. If the car does not crank, IMMO OFF WILL NOT WORK, because immo off RELEASES the ECU START, not the KEY START. (You can try the bypass start-relay method in the engine-bay fuse box.)
4. Immo off means starting before, without a transponder chip — only on standalone ECUs. But new immo off solutions now support replace-ECU only. That means key and BCM/Dash synchronization must be in a good state (MB MED17.7.2, VAG DCM 6.2v, etc.).
5. Immo off actions are done in the Engine ECU, meaning the ECU releases the start signal — but you may need to give the start (CRANK) signal to the car when the key ignition is turned on.
6. If the car key is not matched with Dash or BCM, some extra problems are not unusual, like a dash immo message and windows not working (for example on Audi cars).
7. Main rule: remove the immobox connector or immobox coil connector, or sometimes cut the immo line from the ECU or wires if needed by the immo off method.
8. You need a good MCUID on newer ECU types. It is your responsibility to ensure the HW is compatible and the SW is 100% compatible with your vehicle.
9. You need a checksum (many flashers can do it automatically while writing the file, others not — you can find free checksum tools in the download section too).
10. VERY IMPORTANT !!! Some new ECU types are non-clonable 1:1 like older ECUs. Now they have many anti-tamper methods (SHE, MCU ID, PASSWORD, OTP, etc). If you don't know them and someone before you tried to clone or messed with the original dumps, the ECU can become unusable — NON-RESTORABLE too. You would need a new used SAME ECU. You will probably notice it when you cannot read or write to it because of a lost/unrecoverable PASSWORD and disabled SERVICE MODE after wrong flashing. This is not a newbie-friendly procedure — be warned and always work on the safe side respecting the basic rules.
11. Some immo DTCs, "ECU Blocked" messages, immo lights etc. are normal because this is immo off. We do not repair the immo system. If you don't want any abnormal status, please repair the immo system.
12. When you need support, be sure to email caliskan71@gmail.com the vehicle's past failure history and all details with your user number. Please send the brand, model, production year, engine type, gear type, ECU image and full files.

Why does a SAFE error appear on the dash after immo off?

Because this is immo off. If you don't want abnormal status, please repair the immo system.

There may be more than one reason why the "SAFE" message appears on the screen after the immo off process in VAG group vehicles. But usually the main reason comes from a communication failure between the BCM or DASH and the KEY.

The reason for the error messages on the screen is 99% not caused by the ECU. If you do not want such messages, you will need to add a key to the BCM or DASH, or repair the BCM/DASH-to-key communication.

This message may also appear in some cases with an incompatible engine ECU type. It could also happen if only flash immo-off is done on old-type VAG ECUs — in these ECUs you may prefer to perform immo-off in EEPROM. The same applies to PSA and other brands.

What is the MCUID?

Some immo off operations (especially new generation ECUs) need the MCU ID to be performed. You cannot change the MCU ID — it is OTP (One Time Programmable). You can see the MCUID on the main screen or in the file name while reading the ECU with the flasher.

It can look like 400XXX ... 0000, usually 16 or 32 hexadecimal characters. This information can also be encrypted in the files. Some devices show the MCUID incorrectly — in this case the immo off file does not work in the vehicle and it closes the ECU communication.

4B46915100001820 is not a valid MCUID! Some tools label this as a CHIP/CPU ID, but you need the MCUID, which is unique and in MD1/MG1 units begins with 40xx, 43xx etc. The MCU ID is usually 16 or 32 characters long. It contains only hexadecimal characters — IDs containing any other characters are definitely corrupt.

Examples

The immo systems in new vehicles are not as old-fashioned as before. In classic old vehicles, even with a key fault, you could start by disabling the immo — but new systems are not like this. For the vehicle to work, the key must be synchronously matched with the BCM or dashboard.

In addition, the steering column lock (ESL / SCL) must also fully work or be deactivated with an emulator, or cancelled from the BCM unit. Remember: if the vehicle does not CRANK (starter motor not turning), the immo-disabled ECU will not be activated and the vehicle will not start.

Why could some files be wrong?

Every flasher uses different read/write methods. For example KESS3 has many bugs after the last update (PCR 2.1, MD1CS003 etc). Autotuner does not make checksum and does not properly perform the procedure to flash back the whole ECU backup.

KT200 may read a bad MCUID. OBD read files / partial virtual files do not include immo blocks. We prefer Flex / PCMFlash flashers for the cleanest dump files, and good well-known programmers for external EEPROM reading when needed (older ECUs).

Special notes

Valeo 56.xx are very sensitive ECUs. First thing: original and used parts MUST have the same numbers AND same CODING — please compare both ECU label photos and codings. Which flasher was used for reading and writing? Every flasher reads and writes differently. We prefer Autotuner Boot mode or Flex (unlocked mode).

Are you sure the MCU ID is valid? Has anyone touched the files before? Did you try cloning before? If someone tried to clone before, the ECU can be killed and give "INTERNAL ERROR". Please see "Why does IMMO OFF not work?".

MD1CS006 and MD1CS016: Virgin available only for original ECUs, not for used ECUs (because of the SHE module).

Renault / Nissan BCM: If you delete the keys in the BCM key codes, the vehicle will not start — immo off will not help. This is a COMMON PROBLEM in Renault/Nissan; you need to bypass the starter relay and modify wiring to start.

How should you read 93Cxx — 16-bit or 8-bit?

As a general rule…

Read/write as 16-bit if: pin 6 (ORG) is connected to pin 8 (VCC), or pin 6 (ORG) is left unconnected.

Read/write as 8-bit if: pin 6 (ORG) is connected to pin 5 (GND).

Best wishes,

OTOCHECK Team