[thstone]

I remove the immobilizer fairly often.

Sorry to say this again, but check that the connectors are firmly seated. If still no go, then pull off the connectors and look for bent pins.

The wire harness is fairly short and its easy to pull it out when re-installing everything. And yes, while it can only go in one way, I was able to bend a pin once and even though the connector was seated, the bent pin kept the car from starting.

You may want to pull the seat again to get it all working without having to work in the limited space under the seat.