Start Inhibit Relay?

[JebLacey]

The problem disappeared for a few days, put over 150 miles on the car! Could not stay out of it. Now it is back. Went out to the garage to go to the store, and turned the key... no CEL :( Hasnt started in about 1 hr. now. I noticed something else... when it does not start, I hear a few clicks from the back of the car. Today, I finally had my wife turn the key to accessory so I could locate the source of the clicks. It sounds like it is either coming from the DME Relay (slot 1) or the Start Inhibit Relay (slot 7). I swapped the DME Relay with my engine fan, no dice. I dont have a relay that matches the Start Inhibit Relay, so I cannot see if there is a fault in it.

Is it normal to have a relay click like that (so loud that you can here it with the trunk shut), and is there any relay I can swap with this one to see if it is the problem?

Not thinking ignition but replacing anyhow... on my way to Auto Zone to order it...

Thanks for the help...

[JebLacey]

Ok... so it is getting really frusterating. Car started again last night, drove it about a block, and the CAN Bus fault happened again. When I stopped the car, the CEL would not come back, and the car would not start. Bout 20 mike later, it fired, kept the CEL on (due to the CANBus), and drove home. Fired this morning no problem, drove it quite a bit, then came home. when I left the house again, at the same location, the can bus fault happened again one block from the house... i mean, the same identical spot. Coasted to a stop, and tryed to restart... no CEL, no start. Its been a few hours now.

Someone in the PPBB forum had the same problem i am having with the CEL and the no start. They never posted how they got it resolved though. I am so completely lost. Could a bad ignition switch (which is what i keep hearing from some locals recently) cause a canbus fail, and a no CEL at Accessory?. Not to mention, could a bad ignition switch cause a car to die while rolling? I suppose it could, but does this sound familiar to anyone?

Someone tell Loren to sneak back and fix it again! :)

Brian

[JebLacey]

Ok... so I went out and bought a digital Ohm Meter. Want to trouble shoot this canbus thingy... what is the Porsche special tool 9616, and is there a home remedy for one if you dont have one?

[Loren]

Good battery? Good ignition switch? Good grounds on the chassis?

Those are the things I would check first since this is a very unusual (and intermittent) failure.

[JebLacey]

Ok... so grounds points 8 and 9 right? Switch will be replaced on wednesday, and the batt is good.

I am gonna check the grounds, check the Tip... ect. Question: Not too long ago you gave me some instructions on checking the canbus failure. Do the portions that involve the ECM being disconnected have to be done ignition on? Cause wouldnt this cause a fault in itself? Or are the checks (between pins 85 and 86) done with the key off?

[Loren]

The first two tests are continuity (ohms) so no power. The last two tests do require power so you will need a good ignition switch to get reliable readings.

[JebLacey]

I have replaced the ignition switch. Was really easy. Thanks for the great instructions, Loren.

Problem is, however, that the ignition switch was not the problem!

I took it out for a spin, and sure enough, after about 15 minutes of driving, it went to safe tranny mode while in 3rd gear, and the engine died. No CEL when I tried to re-start, so it is currently sitting about 3 blocks from my house.

I am gonna start a new post to clear up what is happening. Perhaps someone will have another idea!