Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
When a key is inserted in the ignition, the contacts located in the ignition cylinder contact a resistor pellet located in the key. The instrument cluster (IPC) measures the resistance of the key pellet. The IPC then compares this value to a value stored in the IPC's memory. If the values match, the IPC allows engine to start.
If the values do not match, the IPC does not provide ground to the starter relay and sends a request to the PCM ( engine computer) to disable fuel injectors control.
These vehicles are well known for ignition lock cylinder issues.
You should measure the resistance of your key and then make sure you get the same stable reading at the connector C202 ( terminals E12 and E13, base of the steering column) even when you turn the key through the all positions. If your reading is unstable, then replace the ignition lock cylinder.
Greetings and Welcome to Just answer. Vlad is offline.
This is a new question so I shall answer you. I have been working with Luca on those systems.
The TDM is a stand alone system and is left of the brake pedal along with the Theft enable relay beside that. It is passkey 1. (VATS)