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1996 Cadillac Deville
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4 Posts
Discussion Starter #1
Drove it home one day and there is a slow oil leak so I was just putting some oil in, I accidentally left the key on and the battery drained. Battery was kind of old anyways so decided to replace it. With the new battery the car would crank but wouldnt start. After a while saw the "Security problem car may not restart".

Did some research and decided to bypass the VATS system and tried to give it a go again. Again same thing car would crank but would not start.

Interesting thing is whenever I unhook the battery and rehook it up the first time I try to start it, it sounds as if its right about to start and then just cuts off. And then it goes right back to its cranking and not starting.

Any help would be appreciated, actually is my future inlaws car that they are letting me borrow to get to and from work so if anyone has suggestions please give them!!!

Thanks
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,781 Posts
Interesting thing is whenever I unhook the battery and rehook it up the first time I try to start it, it sounds as if its right about to start and then just cuts off. And then it goes right back to its cranking and not starting.

Thanks
Check your fuel pressure.
 

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1996 Cadillac Deville
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4 Posts
Discussion Starter #3
Checked the fuel pressure, when turning car on goes to between 45 and 50 psi and stays pretty steady, the same for when I try to start it fuel pressure is at a steady 45 psi.

Could it be the fuel injector relay?
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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86,781 Posts
You can rule out the fuel pump.

Have you pulled the DTC's? That would be the place to start.
 

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2002 Eldorado Biarritz
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451 Posts
On this system. The IPC/Instrument Panel Cluster provides a ground path for the starter relay. This output can be disabled to prevent vehicle theft disabling the ability of the engine to start. The IPC also sends "fuel enable" signal to the PCM indicating that the PCM may enable the fuel system. Typical Pass-key II operation is to allow the fuel pump to run no matter what. On the first start the PCM will operate the fuel injectors for 1 second to account for a potential delay in receiving the fuel enable signal due to a lag in modules waking up, low system voltage, etc. If the fuel enable signal is not received the PCM/Powertrain Control Module will stop operating the injectors and the vehicle will either stall or never start. After that initial attempt the PCM will not operate the injectors again until a valid fuel enable signal is received or the system is reset.

To me it sounds as though the IPC is either receiving the correct key signal or is operating in fail enable mode and allowing starter operation while the PCM is never receiving the fuel enable signal. The first thing to do is the check module communication and check for DTC's. Use the sticky at the top of the forum to pull DTC's from the instrument cluster. Record the output and report back here and I will help you as best I can as time allows.
 

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1996 Cadillac Deville
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4 Posts
Discussion Starter #6
Here are the codes, I wasnt able to find them with the letters included but by just looking up the numbers they were able to match up to the link in the sticky:

PZ1558 History- this one had two that matched:1. Cruise Control Servo Low
2. BCM ERROM Checksum Error
PZ2470 History- Daytime Running Lamp
PZ2473 History- High Beam Fault
IR2255 History- Couldnt find this one
PC0603 History- Control Module Long Term Memory Reset
PC1631 History- Theft Deterrent start enable signal not correct
IP1552 History- Keep Alive Memory (KAM) Error
IP2710 History- PASSkey Open/Shorted Pellet
IP2750 Current- PASSkey Data Communication Failure

Thanks for you input and help!
 

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98 DeVille, 97 DeVille d'Elegance
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7,345 Posts
Current code is Passkey problem... That will keep car from starting. Aound like time for a VATS bypass. If the wires break in the column or key pellet goes bad it will keep car from starting.
 

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2002 Eldorado Biarritz
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451 Posts
It appears as though the PCM has lost the fuel/start enable password probably when the battery died slowly. The password is a handshake between the IPC and PCM the PCM must learn the password so that it knows it can trust the enable signal coming from the IPC. Unfortunately, some bypass kits may even if properly installed inhibit the sequence of events necessary for the PCM and IPC to shake hands again. If you PM me your email address I can email you the 30 minute relearn procedure. If that doesn't work with the bypass installed my recommendation would then be to return the vehicle to stock and try again. The 30 minute relearn may have been all that was necessary from the beginning. If that doesn't work we'll cross that bridge when we get there. The P1631 and B2750 (IP2750) are hallmarks of needing the password learned again which is accomplished through the 30 minute relearn. You can probably find the 30 minute relearn on the internet somewhere but if you would like I can email you an exact copy of the service manual entry along with my tips for a successful relearn.
 

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1996 Cadillac Deville
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4 Posts
Discussion Starter #9
Update: Performing the 30 min relearn WORKED! Didnt fire right up at first felt like it was barely holding on but that was because the battery was low so went out and took a drive on the freeway everything seems to be in working order. Cleared the codes and even tried to start it again for a couple times and it fired up beautifully everytime. THANK YOU!!
 
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