How to get rid of 993 Immobilizer

[silver911rdb]

Does anyone know how to bypass or eliminate the immobilizer on a 1996 993 C4S?

[livesportm]

Most guys that reflash the ecu can remove it.

[Don Plumley]

A 96 is problematic AFIK, if you have a 97+ you can have the chip reflashed, Steve Weiner on the board does this. Not sure if you can do it to a 96, would like to know if you can.

[Sonic dB]

Originally Posted by Don Plumley

A 96 is problematic AFIK, if you have a 97+ you can have the chip reflashed, Steve Weiner on the board does this. Not sure if you can do it to a 96, would like to know if you can.

God that is useful...thanx

[Bill Verburg]

On a transplant a chip can eliminate the immobilizer function, but on a 993 just using a non immobilizer chip hasn't stopped the immobilizer from acting as usual.

I'd need to look it up but as I recall there is a relay that needs to be jumped to bypass the immobilizers effect.

[vintage guy]

I think it is safe to say that a method of eliminating the Immobizer function is something that many of us would dearly like to know. Please give us any information you have.

[Speedik]

Hello

Owning an euro 96' with OBD1 - I am very much bored by the immobilizer and want to get rid of it.
I have studied the wiring diagrams and it seems that the immo is just a radio switched +12V feeder : meaning that it just feeds the Motronic at Pin 27 with TERM 15 +12V.
If not mistaken we just need to replace this source of TERM 15 +12V.
I do not imagine the immobilizer sending a coded signal to the Motronic.
My studies showed that I need to:
1- Put a Jumper on relay R61 between Pin 7 and 3
2- Put a Jumper on connector X4/1 between Pin 10 and Pin 2 (Term 15 feed to DME)
3- Connector X 4/2 : cut Pin 12 (Or/Bk) ??? : as per manual when changing wiring diagram (action not yet understood ...linked to diag socket)

These actions have not been tried and would be great to have your point of view.
Regards
Nicolas
P993 96'

[Bill Verburg]

Originally Posted by Speedik

Hello

Owning an euro 96' with OBD1 - I am very much bored by the immobilizer and want to get rid of it.
I have studied the wiring diagrams and it seems that the immo is just a radio switched +12V feeder : meaning that it just feeds the Motronic at Pin 27 with TERM 15 +12V.
If not mistaken we just need to replace this source of TERM 15 +12V.
I do not imagine the immobilizer sending a coded signal to the Motronic.
My studies showed that I need to:
1- Put a Jumper on relay R61 between Pin 7 and 3
2- Put a Jumper on connector X4/1 between Pin 10 and Pin 2 (Term 15 feed to DME)
3- Connector X 4/2 : cut Pin 12 (Or/Bk) ??? : as per manual when changing wiring diagram (action not yet understood ...linked to diag socket)

These actions have not been tried and would be great to have your point of view.
Regards
Nicolas
P993 96'

There is communication going on between the immobilizer and the DME.

The forst thing I tried to by pas it was to install a non immobilizer chip. No go.

additionally i've tried an immobilizer chip in a non immobilized car, again , no go.

I believe that 2 things have to happen
1) chip change to non-immobilized spec
2) jump relays perhaps as described above.

[Speedik]

If I have time I will try this sunday to bypass the immo.
As seen in the wiring diagram the immo act as a relay with 2 function:
1- Activate the R61 Starter relay
2- Activate the DME with TERM 15 +12V
In the wiring only one wire is routed between the immo and the DME and it is described as +12V feeding.

As per the wiring the change of eprom cannot change the physical "mission" of the immo.

Let's hope that the problem is only the presence of immo and not also an eprom dedicated soft in the DME.

BTW I am looking at OBD 1 wiring with a 55AMP connector for the DME - in the US you seem to have 88 pin connector for the DME when car equipped with multi lambda sensors.

[930gt-40r]

I have started a TT with a jumper going to the starter side of the imobalizer relay and it fired right up. Does any 993 have a more inteligent immobalizer? This also worked on a 99' F355 that has the same immobilizer setup that the 993 does.

[Steve W]

The 96-98 Euro 993 and 993RS immobilizers can be defeated, but removing the immobilizer code within the DME chip is necessary. I'm not certain if other relay changes need to be done though.

[Bill Verburg]

Originally Posted by Steve W

The 96-98 Euro 993 and 993RS immobilizers can be defeated, but removing the immobilizer code within the DME chip is necessary. I'm not certain if other relay changes need to be done though.

I have 2 custom chips w/o immobilizer code, neither will allow the car to start w/o a jumper

chassis -'95 US, DME is '95 US, engine is '97 RoW

[ErVikingo]

Is there an answer to this? 97 C2S with PITA inmobilizer......

[Bill Verburg]

Originally Posted by ErVikingo

Is there an answer to this? 97 C2S with PITA inmobilizer......

2 things are necessary, this worrks on my own OBD1 car and I've seen it done on a 993tt so it should work on an OBDII '97
1) non immobilizer chip
2) non immobilizer relay to replace R61 relay

read this thread

[carsonmx114]

Small yellow/black wire from immobilizer to starter relay needs to be energized when you turn the key to the start position, or you could just jump the start relay. I lifted my fuse panel and cut the yellow/black wire then soldered it onto the wire from the key (maybe a large yellow, I can't remember). The problem you may have is the immobilizer is the part that recieves the signal from your alarm remote, it then sends a ground pulse to arm and disarm the alarm. My immoblizier was missing when I got my car (rolling chassis) so I installed a keyless entry system under the driver's seat, now my alarm works fine with no immobilizer.

[Thespeedofsound]

I have found a fix/bypass for this immobilizer issue as long as long you still have a semi functioning remote. This has been working 3 months on a customers 993. I just did the same fix for his sons 993 and both have been able to start it everytime they get in the car without having to disarm the factory immobilizer from the remote ever again. The bypass cost $200 if done here in denver or plus air fair if cheaper than shipping it to me...LOL... I also offer doing a viper alarm to regain keyless entry and security feature again for $500. I am looking for other models that this may work for... This was found after Porsche couldn't program new remotes at the dealership and I was asked to help... Let me know as I'm always up to a challenge...


Thespeedofsound@comcast.net
Bill Howard
720-732-5479

[Thespeedofsound]

**UPDATE**
Since I posted this years ago, I’ve done quite a few of these bypasses. They’ve all worked perfectly with no issues or side affects. I did discover that when doing this bypass we do have to install either keyless entry or an alarm every time to achieve door lock functionality. This whole process takes a day at our shop to complete. Be assured that we are not a hack shop, and that any work we do is completely reversible if wanted. The total cost will be $450 bypass/keyless or $550 bypass/alarm...
Premier Car Audio
625 E. 70th Ave #1W
Denver, Co 80229
Premiercaraudio@comcast.net

Originally Posted by Thespeedofsound

I have found a fix/bypass for this immobilizer issue as long as long you still have a semi functioning remote. This has been working 3 months on a customers 993. I just did the same fix for his sons 993 and both have been able to start it everytime they get in the car without having to disarm the factory immobilizer from the remote ever again. The bypass cost $200 if done here in denver or plus air fair if cheaper than shipping it to me...LOL... I also offer doing a viper alarm to regain keyless entry and security feature again for $500. I am looking for other models that this may work for... This was found after Porsche couldn't program new remotes at the dealership and I was asked to help... Let me know as I'm always up to a challenge...


Thespeedofsound@comcast.net
Bill Howard
720-732-5479

[914TWO]

Since my immobilizer still is working well, I have not tried this, but on page 96-11 of the Bentley service manual for the 993, it explains the procedure of how to deactivate the immobilizer system. As mentioned in the post above, it would appear you would need to install some sort of aftermarket alarm system to lock doors and have a functional alarm.

[wesleyc]

I did just what Bill V. Said. On my 95 993 and it works great. Door locks still work. Even the little red lights on the doors blink when locked