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Hi. A few weeks back my car developed a fault with an immobiliser. I drove the car regularly and the battery never went flat. Overnight my car developed the following fault. In the morning my fob could not open the car I used the key on the driver's side and it opened the driver's side door only. Curtsy light remained off even when I opened the door. When I turn the key in the ignition to position all control lamps were on and off as usual apart from green key flashing. If I try to start the car I can hear the starter motor cranking the engine but the engine would not start. I called in the locksmith and sadly he informed me that the immobiliser failed to communicate and he could not program my keys. What would be the best course of action swapping the ECU and ignition key or bypassing the immobiliser? Personally, I have some experience with electronics and soldering therefore bypass chip would be easier. Can anyone recommend where I could source an immobiliser emulating chip?
Probably not the immobilizer, that is just a symptom.
It is probably a failed MICU and that is very common. Search around here and the rest of the web for MICU failure. Way more common than it probably should be.
If you are really savvy with electronics flashing the eeprom with a known good rom file seems to fix them.
Thank you very much for your rapid reply! I will read about it tomorrow and see what I can find. Just to double-check is MICU part of ECU? And is ECU located behind the glove box?
I searched the web for the wiring schematic of MICU and it seems that it is a few relays and fuses. I pulled what I think is MICU (picture attached) and checked all the fuses once again all good. Apart from fuses, it has two relays and an interrupter for indicators. I swapped relays around hoping to see fault in a different place but it seems that both relays are fine too. I sometimes program the microcontroller's EEPROM with new firmware. I could try to program my ECU. This assumes I can find firmware and programming interfaces. However, if I have a wiring/hardware fault would it fix the issue?
Yes that is the MICU you have pictured. If you can get your hnads on a known good ROM file you can reflash the EEPROM and it should work again. At least that is what we are finding.
After a close look at my ECU, I suspect that my car was modded in the past as I think my EEPROM chip is missing. Any chance someone could confirm my suspicion?
This should be the eeprom with the immobilizer data on it. I think it can be removed but it will cause a permanent check engine light. There is also a way to reprogram that eeprom to not check for immobilizer. The information is out there on the webs.
Thank you for the info. Tomorrow I’ll remove the chip to get car running. I will also look for ROM and look for memory reader and appropriate software. Apart of check engine light is there any other disadvantage of removed EEPROM?
I am not that worried as the car value it is less than half-decent TV 🙂 Also, it is not obvious that it is modded. So I asked the work college to remove the EEPROM chip with hot air. After fitting ECU back in the car the car started the first time! Fantastic result. I noticed immobiliser, engine management and ABS warning lights. When checking the error with the OBDII scanner it printed P1607 which as far I know is a board damage error. Rightly so as one of the ICs is missing. Sadly in the current arrangement, central locking and access to the trunk are off-limits. My next step will be programming IC with ROM for the same ECU. Perhaps depending on availability I will consider buying a new EPROM IC.
Just rewrite the EEPROM you have. Probably nothing wrong with it other than corrupt data is currently on it. There are sources out there for ROMs with immobilizer code removed.
I will. Checked already and there is few forums with EEPROM hex content available. Will talk to same work college as he indicated that we have adapters for this chip as well as EEPROM reader. Oddly, that content got corrupted one would think that ECU voltage rails are stable, the PCB is shielded with the metal case on top of that my battery never completely died so power was always available 🤔
Thank you for all the help so far. In process of finding suitable EEPROM programmer. Sadly a lot of cheap ones form amazon do not have either documentation or official software. Also need to verify sources for ROM. Just for clarity my engine management light should go off once EEPROM is fitted back? Will I need call for locksmith to program the keys?
im having about the same issue an European Honda Civic 2001-2002. I About 6 weeks ago my Civic stopped starting. I got home from work and about 30 minutes later wanted to get some groceries. I noticed when i entered the car my electric door locks did not respond and so my interior ceiling light di went on neither. Then got this green flashing key. I checked all fuses but did not see any burned ones. I tried some videos which all showed checking fuses but this did not help. Eventually i got i towed to a local garage which is good with European cars. It took quite some time before i got a call that they could not find the issue. They metered everything and said all should be good. They do not have the proper computer to read out everything, but said the immobilizer should work. So the stated ordering a complete kit, so immobilizer, keys and ECU second hand from Europe and ty that. Well that was 2 weeks ago and today i heard that didnt work neither. They are now trying some connections they have in The Netherlands to see how they can bypass the immobilizer, they had tried that earlier but could not get it to work.
I found some threads about using an IMMO emulator and told the technician, he did not know of that. I find that a bit weird because i found out that is a key step in bypassing the immobilizer and keeping the OBD to have eadout.s
What i also find strange is why my door locks and interior light dont respond to the key. Normally the interior light comes on when i enter and fades out over time. When i physically switch it, it does work. Thats is strange right?
If i'm correct the lock and lights are connected through the MICU and he also said they are separate. It should not matte. Still find it weird that all 3 parts stopped working at the same time. Also that that second kit does nothing at all neither
The dome light fade is the IMCU as are the power door locks.
The physical switch on the dome light is just connecting the dome light to ground at the switch, no IMCU for that.
Well what i find weird is that all of these 3 symptoms appeared at the same moment. Can the ECU or Immobilizer be connected in a different way. I mean outside the fuses, could it be some other loose connection can cause issues with all 3 components?
@Rombout Sorry to hear about your car developing the same problems as mine. Sadly you already towed it to a garage as you still can start the car if you follow instructions in this tread.
Regarding courtesy light and door switches. True, door switches are mechanical but they do not conduct current to the curtesy light they simply signal the ECU that doors were open hence when you close the door light dims gently instead of simply switching off.
To summarise my findings removing the EEPROM allows you to start the car. However, the engine management light is permanently on. Also, many other issues are occurring fog lights control is disabled, central locking is disabled, trunk lock is disabled, courtesy light is disabled. Lastly, the performance of the engine is affected. I believe that the car is running in “limp mode”. I noticed that my petrol engine started to sound like diesel as well as fuel consumption went noticeably up.
@Ryanthegreat1 After my disappointment with the USB EEPROM programmer from amazon I used Arduino as a programmer. I read the content of my EEPROM and it appears to be empty all 128 words read “FFFF”. Not sure if my EEPROM got damaged or perhaps my coding is not that great. I am awaiting a review of my code to verify the result. Reading the same subject people that erased EEPROM by overwriting the content to “FFFF” had issues with the engine management light being permanently on. I would love to find some good materials to explain exactly what is the content of that EEPROM word by word. Also, SOIC8 clips sound great they are worth getting.
@Rombout Regarding emulators I purchased one as the last result. I intend to try to use a new EEPROM chip and ROM first. I will keep you up to date if I manage to fix the problem. Interestingly, the ECU swap did not work I considered it myself. So the mechanic swapped the ECU, immobilizer and keys from the working car? What I mean was the car verified perhaps it suffered from the same issue.
Ryanthegreat1 Reading about the subject it slowly sinks in what you stated about the importance of MICU. To my understanding, MICU is a switchboard between sensors, switches and ECU. Is MICU serialised? Meaning if I change MICU I have to change the full kit to MICU, ECU, dials and barrel? Or can I program an immobiliser to recognise the MICU?
On this generation the MICU is not programmed in. Should be able to swap between cars no issues. Just needs to be from the same transmission type. AT or MT.
Does your dome light fade when the doors are closed? Remote unlocking work? There are a few other symptoms as well.
10-20-2021, 12:30 PM
Faulty immobiliser Honda civic 2002.
