911cedric

Hi there,

i've decided to pull a project car out of my garage. It was sitting there for 5 years, and i don't remember if i had a remote for this car. It is a late 95 tiptronic cab
The problem now is that the immobilizer does not turn off and it is thus impossible to start the car. The car is sound technically; i have inspected pretty much everything and it would start if the immobilizer wouldn't be ON. The light remains on the dashboard. The car locks and unlocks from the doors and the alarm led blinks twice; however, while messing with the car, i never triggered the alarm which makes me wonder if it is actually working

I have checked connections on the alarm computer, immobilizer and DME, and everything is stock, so i've ruled out an aftermarket alarm.
However, the rivets on the protective plate above the DME and immobilizer were gone and replaced by 10mm bolts, the DME had been moved too, so something was done there.

I have scanned the car with the PST2, and the funny thing is that the alarm computer reads that the remote function is OFF; i haven't compared with the datas from another car, but this is what it says. Also i have a stubborn number 25 error in the alarm computer saying there is a radio signal cut during the alarm activation.

The lack of remote, the function turned OFF in the alarm computer, the security rivets removed from the DME, all this makes me think that maybe the previous owner had the immobilizer neutered and the DME patched. Then, either the DME or the immobilizer or both could have died in the meantime

However i have no clue of how to verify this.
I can pull the immobilizer code and get a remote from the dealer, but if the immobilizer was deleted nothing will happen there.
I can swap the DME and immobilizer from another car, but that won't tell me which one is wrong given that they work together and have to be coded

So how to know, and is it possible to turn it back on after the dme modification?

thanks
cheers

ECU Doctors

911cedric,

Open the ECU DME cover and take a look at the memory chip.

When we bypass the Driver Block / Immobilizer from these Control Units, we put our own memory chip and it will have our label on it.

If we didn't do it, and this was done by someone else, then it will most likely have a non-oem sticker on it as well.

Lorenfb

Many over the years had non-immobilizer chips for the '95 DME ECM to eliminate
the immobilizer. It was a simple process to obtain a non-immobilizer DME ECM,
pull its chip and make multiple copies. Hardly requiring any great skill, effort,
or exclusivity!

nine9six

Welcome back, Loren! Have you been on a hiatus?

911cedric

Hello there,

thanks for the feedbacks
i was thinking about doing it since everything is taken apart;
I will remove the DME metal cover tomorrow and post a picture.

In case everything is stock, i may encounter problems programing the immobilizer because the led alarm light blinks twice; i got this permanent number 25 error (radio signal cut when activating alarm) and do not know what this means

I can still send the 2 units to a shop to be checked, but i'd rather find the problem by myself

911cedric

of so FYI error code 25 of the alarm module is thrown when no terminal 86 S recognised Possible cause of fault - Fuse E1 faulty - Terminal 86 S is not detected when terminal 15 is switched on - Short circuit to ground/open circuit in the wiring between the alarm system control module and the ignition lock - Ignition lock defective

alarm module test
Connector 1 is the blue connector
connector 1 pin 16 orange wire, at ignition on should have 12 volts
connector 1 pin 36 Black/brown wire---should have 12 volts at ignition on as well

ECU Doctors

911cedric,

After reading about your number 25 error, I think that you are going in the right direction, in terms of checking your ignition switch and fuses.

However, I am not understanding your pinouts.

See here the pinout for the 993 Alarm unit: http://site.ecudoctors.com/tech-data...arm-Pinout.pdf

There is no pin 36, and pin 16 is a glove box contact that is a ground. So I'm not sure where you got that info.

Now in terms of "programming the Immobilizer", and I'm assuming that you mean to program a Remote, you will definitely need your car's 4 digit Immo Code.

Check for this code in your owner's manual, because I just looked at the picture of your Immo and the sticker with the number is not there.

Your ignition switch has to be perfectly working in order to program a remote, and of course your Immobilizer.

Here is a pinout for the 993 Immobilizer for when you get to this part: http://site.ecudoctors.com/tech-data...ut-diagram.pdf

Lorenfb

If you have the Porsche factory immobilizer:

1. The engine should at least crank if the immobilizer is O.K. and disarmed
and relay R61 is O.K. and your ignition switch (#50) is O.K.
2. The DME ECM having a non-immobilizer chip or not is secondary to having
the engine at least crank.
3. The immobilizer requires a remote signal to deactivate it and to allow
the engine to at least crank, at the same time the immobilizer commands
the DME ECM to allow the engine to run.
4. The immobilizer automatically becomes armed after a period of time.

Bottom Line: The immobilizer must be disarmed 1st via a remote fob.

911cedric

Thanks for the input
the engine doesn't crank and the fuel pump doesn't start
There is still the immobilizer on the dashboard; when the contact is on, the immobilizer light turns off after a while and turns back on again. Not sure how this light should behave if the immobilizer has been deleted

911cedric

Yes, sorry i had the pinout for a boxster
thank you for the document
All the fuses are good in the trunk and on the alarm unit.
One question; in case the DME would have been patched, would the immobilizer light still be turned on when the contact is on?

I have can swap the alarm unit with another car and see how it goes.
Or just test the pins. I haven't checked the relays in the engine compartment though. Is there one i should check? I believe the start inhibit relay is in the front trunk

How can i test the ignition switch without taking the whole thing apart?
not sure where the wires connect first


As far as the remote programming, how does this work?
I guess it is the immobilizer which has be programmed not the remote right?
I bet the immobilizer has to learn the remote signal signature.
Btw i have a used remote from an unknown car; of course not this one;
I guess they are not exclusive to one car. Can use it with this immobilizer?

ECU Doctors

If the immo has been bypassed, this light will still blink / work, and you just have to ignore it.

Therefore, you'd still need to open the ECU cover to check the chip.

Now you say that your engine doesn't even crank, and the fuel pump ins't working.

Because of this, I'm going to jump to the conclusion that your car's Immo is not bypassed because this upgrade should be done together with changing the R61 starter relay with an OEM Porsche Starter Jumper (964.610.184.00) that allows the engine to crank regardless of any upgrade that your car may have.

I'd say, you are going to need 1 Remote to start this car.

ECU Doctors

R61 is the starter motor relay which is in the front luggage compartment
Correct, the Immo gets put through a sequence that puts it into learning mode. (You need the 4 digit Immo code to do this.)

Then, you press the remote button and the Immo "learns" its signal and they get "married".

You can use a used remote and it can be programmed to your Immobilizer.

Lorenfb

This post seems to have overlooked a few factors:

1. The OP needs to have the CORRECT immobilizer code.
2. The immobilizer must be fully functional.
3. The ignition switch must not have any contact bounce.
4. The key-in-ignition micro switch must be functional & without any contact
bounce.
5. Obviously, any used remote must be capable of transmitting a compatible
frequency to the immobilizer.

Again at this point, the state of the DME ECM is of secondary importance.
The immobilizer must be capable of allowing the engine to crank 1st!!!!!

911cedric

As suspected, the DME has been chipped see picture below, with a performance chip which very probably bypasses the immobilizer

I swapped the alarm computer with a healthy car part, but no luck
so i guess the last possibility is the ignition switch or a dead DME

I'd like to program a remote for this car, but if the immobilizer is neutered, how can i program it to recognize a new remote?

911cedric

ok, so i got the immobilizer code;
but i also found out in the meantime that the DME has been chipped with an immobilizer bypass performance chip

Given that i can't connect the DME with the PST2 (only the secondary modules like alarm abs etc) and that the immobilizer light stays ON on the dashboard, it makes me think that the DME or the ignition switch is dead

I'll test monday the ignition switch by measuring voltage at the R61 relay and see if the relay gets current from the DME/ immobilizer unit