986 Immobilizer Frustrations

[Riley98697]

This week I have been struggling with a intermittent starting issue on my 1997 boxster 5 speed. I replaced the ignition switch battery and clutch switch in hopes that it was something easy. With no effect on my part I decided to let my local dealer fuss with it. $200 later my problem has been diagnosed as the dreaded immobilizer being wet. I. Got a quote of $3600 parts and labor to remedy the problem and it seems foolish to put over half the cars value into repairs. My quest for posting today is to look for more wallet friendly ways of repairing or replacing the immobilizer. 

I will buy a waterproof cpu case and look into roof leaks while the unit is out. 

[JFP in PA]

2 minutes ago, Riley98697 said:

This week I have been struggling with a intermittent starting issue on my 1997 boxster 5 speed. I replaced the ignition switch battery and clutch switch in hopes that it was something easy. With no effect on my part I decided to let my local dealer fuss with it. $200 later my problem has been diagnosed as the dreaded immobilizer being wet. I. Got a quote of $3600 parts and labor to remedy the problem and it seems foolish to put over half the cars value into repairs. My quest for posting today is to look for more wallet friendly ways of repairing or replacing the immobilizer. 

I will buy a waterproof cpu case and look into roof leaks while the unit is out. 

 

Welcome to RennTech

Wet immobilizers are a common every day problem with the 986/987/996 cars.  You may be able to save yours by having someone like the ECU Doctors have a look  at it; otherwise you are limited to trying to find the immobilizer, DME, keys, ignition, and door locks that all match from another car.  Either way, it is going to cost...……….

[Riley98697]

Thanks for the reply JFP! I have an update to my case. I just picked the car up from the dealer and drove it home. I proceded to pull out my drivers seat and remove the m535 unit. I opened the case and inspected the whole thing. The board looks totally clean, all connections are shiny and the board shows no discoloration, corrosion or burns and I see absolutely no evidence of water in the car even after a heavy rain this morning and dry dusty floor under the immobilizer. Any other tests I might be able to try to confirm the immobilizer diagnosis? I have no CEL and no codes on the computer only a car that sometimes does not turn over.

[JFP in PA]

1 minute ago, Riley98697 said:

Thanks for the reply JFP! I have an update to my case. I just picked the car up from the dealer and drove it home. I proceded to pull out my drivers seat and remove the m535 unit. I opened the case and inspected the whole thing. The board looks totally clean, all connections are shiny and the board shows no discoloration, corrosion or burns and I see absolutely no evidence of water in the car even after a heavy rain this morning and dry dusty floor under the immobilizer. Any other tests I might be able to try to confirm the immobilizer diagnosis? I have no CEL and no codes on the computer only a car that sometimes does not turn over.

 

The immobilizer can look clean and still be problematic (cold solder joint, etc.), which requires special equipment to evaluate it.  I would go back to the dealer and inquire how they determined the problem, it could still be real.  Another possibility is the ignition switch electrical section which is a well known failure point on these cars.