Hello,

I need some help with my 99 996 C2. It does not crank. The battery is good and everything seems to power up ok when I turn on the ignition. When trying to crank there is no response. My mechanic scanned the fault code and said it was the Immobilizer. I sent the Immobilizer to ECU Doctors and they could not find any problem.

We want to test the data stream from the rfid coil to the Immobilizer. We have the schematic and see there is a transponder between the coil and the Immobilizer. However, we cannot locate the transponder.

Where is the transponder?
Can we test the coil with an Ohmmeter?
If we use an oscilloscope, what should the signal look like?

Thank you.

 

The transponder antenna is a round ring around the ignition lock. The transponder itself is inside the key head.
There is also a small box attached to the ignition lock that the transponder antenna connects to if I recall.
I thought that when a start was attempted without a valid immobilizer signal that a fault code "immobilizer defeated start attempt" was stored though this might be on newer ones only.

 

Thank you. I will take the switch out and look for the small box.

 

ignition module is your problem. Replace it.

 

@Viper1000 What is the ignition module? There is no part by that name in the manual.

We checked the coil with an Ohmmeter and reads 12 Ohms, which is correct per the repair manual. We replaced the transponder but the car still won't start. When we hard ground the control terminal on the starter relay the starter runs but the engine will not start.

We are not getting any codes now but the car still does not crank. If we get the cheap PIWIS tools mentioned here: https://rennlist.com/forums/997-foru...only-75-a.html will we be able detect the presence of the key with the rfid pill when it is inserted in the ingntion switch?

 

I think he means the Ignition switch. It is a DIY for sure.Ignition Switch Genuine Porsche 4B0-905-849 4B0 905 849 4B0905849 4B0.905.849 | Pelican Parts

 

With the cheap PIWIS clone you will be able to check all the messages stored in the immobilizer. It's a must-have for any 996 enthusiast.

 

Sorry I did mean the ignition switch. Seems more and more lately have been failing.

 

You got that "Some-timers " Disease ...I get that sometimes....lol

Op..yes you need to get that $75 PIWIS set-up... it is invaluable for tricky diagnostics ...

 

Ok, thank you for the clarification. My auto repair lexicon is circa mid-1970s so I thought about the GM HEI ignition module and the like.

 

I have some-timers disease more often than I care to admit.

Thanks for the input on the PIWIS. I will go ahead and get it. Hopefully it will help solve the problem with my car.

 

Nice way of saying I'm getting old and can't remember $hit :P). lol

 

Hooray, my car is fixed and running again! The mechanic found a bad power wire going to one of the computers. Thank you for all your help and suggestions.

I ordered the PIWIS clone. It will arrive in a few weeks. Even though it is no longer necessary to solve the non-start problem, I can have fun learning how to use it and get nervous if the cam deviation is nearing the end of the servicable range at 180k miles.