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Vladgmru, Automotive Electrician
Category: Cadillac
Satisfied Customers: 2667
Experience:  I've been working with American made cars since 1992.
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Hello, I have security problems on a 99 Cadillac Deville.

Customer Question


I have security problems on a 99 Cadillac Deville. This is what I need to do:

" * Unplug the connectors from the TDM/BCM and carefully cut D8 (Fuel Enable or Serial Data) and C11 (Starter Relay Enable) close to the connector; then strip back the insulation on the 2 wires.
* Strip out half centimeter of insulation from D5 (Ignition +12V) and C1 (Ground) - do not cut those wires as they are also inputs to the BCM.
* Connect the pink wire (D5) to T1 on your circuit; then the dark blue wire (former D8) to your output T3, and finally the other 2 wires (C1 and C11) together to T2. "

I need to know:
1. If the car's TDM is integrated in the BCM.
2. The color and positions of the wires.
3. Location of BCM or TDM if not integrated.

Much obliged,

Submitted: 7 years ago.
Category: Cadillac
Expert:  Vladgmru replied 7 years ago.
Hello and welcome to JustAnswer.
My name is Vladimir.
This procedure does not apply to your Deville. You car does not have a Theft Deterrent Module, the Instrument Panel Cluster does these functions.
You car uses a PASS-Key® II.

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.



Customer: replied 7 years ago.
As, I've mentioned, I've alrady tested the lock cyl wiring, and the problem is not there. As a locksmith, I have experience fixing/ypassing the VATS on these vehicle, when the fault is with the ignition cyl/ignition cyl wiring but this is not the case here. If you can supply me with an answer to what ive asked ill be greatful.
Expert:  Vladgmru replied 7 years ago.
I can help you resolving the problem of you car, but I can't supply you with information that does not exist.
Your Caddy does have a BCM but it has nothing to do with the security system.
Your Caddy does not have a TDM.
All the terminals and wires you mentioned in your first question do not match to waht your vehicle has.
If you are sure you have a security issue, you can try to bypass the Passkey system by connecting a resistor of the same value ( as your key) to terminals E13 and E14 at the C202 connector.
Customer: replied 7 years ago.
If this is where the wires from the ignition go, like I've already said, I tried that already to no avail. This car would have a TDM, it just might be integrated with the BCM.
Expert:  Vladgmru replied 7 years ago.
Yes, C202 connector is a large connector where the wires from ignition switch go.
Sir, I do not want to argue, please just believe me that your caddy does not have a TDM.
If your ignition key has a pellet resistor, then this system does not utilize a TDM and it has nothing to do with the BCM. The BCM controls many things but it wouldn't prevent engine from starting.
You said you had security problems on a 99 Cadillac Deville.
Could you explain what the problems are?
Customer: replied 7 years ago.
This is what I'm trying to do:
I've already tested the wiring and tried bypassing with the resistor, which things that I've done before on other cars. On this, the problem is deeper.

If you can take a look at that site and provide me with clearer instalation info, its worth more than 30 dollars for me.
Expert:  Vladgmru replied 7 years ago.
I have checked this website .
The function of the TDM is incorporated into the IPC.
1) The "Starter Relay Enable" wire is the Yellow'/Black wire that could be found at the IPC connector C2 terminal A8.
2)The "Class 2 Serial Data" wire is the Purple wire that could be found at the IPC connector C2 terminal B5 or C3 terminal D1.
Now you can perform the advices from this website.
Hope it works for you.
Vladgmru, Automotive Electrician
Category: Cadillac
Satisfied Customers: 2667
Experience: I've been working with American made cars since 1992.
Vladgmru and 2 other Cadillac Specialists are ready to help you
Expert:  Vladgmru replied 7 years ago.
Thank you for accepting my answer.
Please let me know the end of the story.
If you need more information concerning this issue, you can always come back and reply to this thread.
Good luck.
Customer: replied 7 years ago.
I will. At the moment I'm still trying to gather all the components for the bypass unit. If you can send me a diagram for the port and a rough description of where it is, ill greatly appreciate it
Expert:  Vladgmru replied 7 years ago.
What are you calling "the port "? Do you mean a connector of the IPC?
Please clarify it
Customer: replied 7 years ago.
I mean the place where the wires are located and a good way to identify the correct wire. How do I identify the ipc? Is it the part the ignition wires go to? Ipc connector c2 terminal b5 (and so on) doesn't help me much if I don't know where the ipc is and don't have a diagram of it.
Expert:  Vladgmru replied 7 years ago.
IPC stands for Instrument Panel Cluster. It is a device in front of a driver that contains speedometer , tachometer, warning lamps, and gauges. :-)).
Of course the IPC connectors are located at the back side of the IPC, so remove the IPC in order to get to the connectors and wires.
Click >HERE< to download the IPC connectors pinout ( it is a.pdf file).
Customer: replied 7 years ago.
hi vlad. Turned out i didnt do it on that car, oe not yet anyway... I do need similar information for a 95 Impala.
Does it have a seperate TDM or is it imbdded in the IPC/BCM?
If it does, where is it?
Wiring diagrams.
Is it a passkey 1 or 2?
How do I pay you from this thread?
Thank you
Expert:  Gm Tech (Cam) replied 7 years ago.

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)



Expert:  Vladgmru replied 7 years ago.
Gm Tech (Cam) has already answered your question so I am not going to interfere in this thread.
If you need something from me, please let me know.

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