Clean the stainless steel rim around the ignition barrel where the key transponder's nib makes the handshake with the immobiliser. A worn nib (that round bob to the left of the key shaft), or dirt/grease or whatnot on the SS rim, can interfere. When it does, you will usually get an
Immobiliser Fuel Disable Signal Received code (in scanner). and the car will be set to limp mode and be quite reluctant to pick up speed, providing even if it does start. A completely flat battery in the key transponder will not transmit anything to the immobiliser.
Don't touch any ECU, BCM, plugs, coils or any other component until you have had a good look at the key and it interaction with the immobiliser. A dead/no-start situation can sometimes mean the immobiliser is in lock-down. (it is not so easy to find out why this is so, and attempted forced entry will not cause a lock-down situation). In a few cases I have seen of no-start, the key often turns out to be the culprit in many cases because people think they last forever and a day — they don't, and when the battery in the transponder dies, it's going to cause problems, including difficulty in coding a new key (you should have a spare key/transponder as a fallback). Another test is to completely arm/disarm the immobiliser:
- Shut all doors.
- Press lock once, press lock again. The indicators will remain on for a few seconds.
- Wait a few seconds.
- Press unlock, press unlock again. Indicators flash normally for unlock situation.
- Start the car.
This process is a variation of the normal lock, except it
deadlocks the doors (e.g. the lock nibs cannot be forced up).
Check ignition relay in console on driver's side finder top.