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Author Topic: Immo off 2.0 MKIV 2002 Immo2 - what am I missing?  (Read 4463 times)
KyushaKitsune
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« on: September 10, 2025, 01:15:05 PM »

Hey all,
Trying to Immo-off my wife's daily - 2002 Jetta 2.0, since the megamos chip in the cluster fried.

What I've done so far:
Built a bench harness, and I am able to successfully read and write the 95040 in boot mode.
Modified the file using eepromtool_04
Confirmed successful write of the modified file.
Reinstalled ECU and cleared DTCs.

Car still starts and dies immediately, and throws code 17978 - 35-00 "Engine Start Blocked by Immobilizer"
What am I missing here?
Does the 2.0 use a different address for Immo on/off flags?
Comparing the two files in a hex editor, it looks like eepromtool modifies more than just the Immo flag locations.
Do I need to edit it manually instead?
Attached are the original 95040 and modified version (which I read form the eeprom to confirm a successful write.)
Thank you for any help you can provide.

ECU
06A906032FP
2.0l R4/2V      G
           4072


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KyushaKitsune
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« Reply #1 on: September 11, 2025, 06:05:08 PM »

Tonight I tried editing the file manually, changing only the Immo flags to 02, and adjusting the checksums accordingly.
Still no luck. Engine start blocked by immobilizer.

I noticed the Immo flag values on my original 95040 are 04, where I would expect to see 01.

I'm out of ideas.  Huh

Attached is my manual edit.

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gremlin
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« Reply #2 on: September 15, 2025, 11:05:17 AM »

I noticed the Immo flag values on my original 95040 are 04, where I would expect to see 01.
I'm out of ideas.  Huh

The original EPROM dump of your control unit is intended for cars sold in the USA, without a factory immobilizer.

This is easy to determine by obvious signs - the 04 value instead in place of the immobilizer byte
and the characters XXXXXXXXXXXXXX instead of the VIN number.


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