Immobilizer test 2003 986 Std/Tip
 

Hi all. I've been driving my MY03 since Sept 2020. Perfect.
Replaced the battery June-2021. (Was 7yo.) No problem.
Vehicle is climate control garaged. The top has never even been wet.

Parked in my shop for 6 weeks with battery tender, when the weather got weird
12.8v when taken off the tender this past weekend.
Key to RUN, fuel pump primes, all dash lights on, just as always.
Key to START....and nothing changes. Not even a 'click' at the solenoid. Dash lights don't dim.

I've run the resync procedure for the keys. Lock, unlock, top, windows, frunk, trunk, everything works as if it rolled off out of the factory. Amps look good from the battery.

Next steps are testing the starter relay at position 7 at the trunk relay bank.
Then check continuity on fuses.
That's when I run out of ideas. I'll spend to fix the vehicle, but I don't spend when there are additional diagnostics I can do without the spend. I'm looking for next suggestions, as well as a test I can do to confirm the immobilizer is working without dropping a financial bomb on testing equipment.

I've got 30 years working on cars, but most of them have been vintage, or didn't have immobilizer systems that were this....ahem, strident.

Suggestions?

Check relevant fuses and relays.
Check the negative battery connect at the body.
Check the connection in the little black box next to your power steering fill spout.
Get a good flash light and a good drink remove your engine covers and have a very good long look at your wiring.
Rodents are known to chew wiring.
If you find nothing wrong then you need to start testing circuits with a DMM

Also scan the DME/ECU for any codes present.
Be sure to check the pending codes area when you scan.
Keep us posted;)

Read my recent post with the same issue. Based on my experience, I would start by reading the car and reporting back here any codes. OBD-II reader will only get you so far - so hopefully you have something that can read the Porsche specific codes such as a Durametric cable. If you don't have a reader, check the clutch pedal switch, fuses that I listed in my post, jumping the starter relay in the trunk, checking grounds, etc.