: !996 Deville help troubleshoot

01-15-08, 06:50 AM
Bought a 96 deville. Love it. Replaced many parts.
When it comes to a stop it may run 5 mins or so then stalls..no shuddering just shuts off. Starts right back up again.

Had it diagnosed. Hard to believe with all the codes that came back the car runs at all. When it's running it's smooth and quiet. Just over 100,000 miles.

No overheating. Is it possible that the waterpump could be leaking on one of the o2 sensors as the car has no problems at higher speeds?

01-15-08, 09:28 AM
Lots of possibilities, but someone in here with a '96 FSM will need the codes to begin diagnosis. Did the shop or dealer provide you with the codes, and do you know how to pull them out yourself: the car will do it for you. Nothing else needed. Look at the top of the N* or tech Tips forums for "Got Codes? Look Here".

If you're not losing coolant, it isn't leaking.........

01-15-08, 11:18 AM
Water pump is no where near the O2 sensors, so you can forget that. I'd start with a good TB cleaning and maybe an EGR cleaning as well. Whether or not they are the culprits, they are probably over due.

01-15-08, 01:56 PM
I did get the codes..list about as long as your arm. They claimed coolant was leaking on an o2 sensor. Their diagnosis was a blown headgasket (surprise there huh?)
If that may codes came back I'm puzzled why it's running at all.

Just really hard to believe as there's no white smoke, no smells, no leaks on the ground, runs like a rocket..not that I'm pushing it at all.

The one code that did come on when I had it inspected the was that the torque converter was stuck on.

But then the service engine light went off and it passed inspection of course the service engine light went back on again. But would that keep the engine from running at idle for more than 5 or 10 minutes?

01-15-08, 08:48 PM
Intermittent fuel pump failure?

01-16-08, 06:09 AM
I think maybe that's where to start. The cleaning and replace the fuel pump. Can't get it to the mechanic till next week. I'll repost then. Thanks a lot!

01-16-08, 08:35 AM
Just found the paper with the codes. I looked them all up. Need a recomendation as to whether I should continue with this car or junk it.

PO135 PO138 PO139 PO141P1139 All oxygen sensors.
PO300 Misifire cylinder
PO603 Long term memory reset
PO7741 TCC stuck off (they told me it was stuck on)
P1520 Tran range control switch
P1599 Engine stall near stall

Then they wrote down everything that would have to be replaced in the transmission. $5000 dollars approx for everything

I bought it for $2500 Interior and exterior beautiful. $900.00 in entire brake system $250.00 new exhaust. Because brake system failed needed $350 in body parts including labor. New tires (of course) $400.00 New battery $100.00

I expected to put some money in it. But with all the problems it appears to have I don't know what to do. Any thoughts?

01-16-08, 04:32 PM
The TCC code is P0741, not 7741. Do a search for it as it has been discussed many times. It is a DTC you can live with for $2500. Not sure about the range control switch.

I would not replace the fuel pump until you prove it faulty. Throwing parts at it can get costly.

01-16-08, 04:44 PM
As much as I love this car I can't see another $2500 going into it.

The problem being in NYS if the check engine light won't go out for inspection they make you junk the car after a certain amount of money in repairs.

Oh well I was hoping againest hope anyway.

The guy at the Cadillac dealership told me that these engines weren't designed well.

I had one that was a diesal years ago ,had the engine pulled and put a gas one in.

Actually I have two Eldorado Indy pace cars in my garage.

My dad always had cadillacs and never seemed to have any problems. But if all the models have this engine I guess I have to find another kind of car.

Thanks Ranger for all your help.

01-16-08, 08:51 PM
WAIT. Don't junk it. Have the other stuff fixed. Clear the DTC'S, then drive it in 3rd for several days. P0741 should not come back if you don't put it in DRIVE.

01-17-08, 08:36 AM
I'm sure I can figure out hoow to clear the codes by the info in this forum.

But are you saying to drive the car for the rest of the time I keep it in third gear?

Will clearing the codes turn off the sevice engine light too?

01-17-08, 09:11 AM
Ok I'll try to clear the codes.
But there is still this stalling problem yesterday when I drove it it stalled at a low speed taking a corner.
I thought maybe I'd try to replace the fuel filter first?
I re read your post about third gear I'll try that also.

01-17-08, 09:53 AM
I used directions below to try to clear codes
Ignition ON, Engine OFF.

Simultaneously push and hold the OFF and WARMER button for 3 seconds and release them.

After all the codes display you will see PCM?

Push and release the HI button and the whole display will light up.

Push and release the LO button and you will see PCM CLEAR CODES?

Push and release the HI button and you will see PCM CODES CLEAR, Wait 3 seconds and then turn OFF the ignition

I get to PCM? and nothing happen I can't get it to ask me to clear codes are these directions wrong for my make amd model?

01-17-08, 11:54 AM
But are you saying to drive the car for the rest of the time I keep it in third gear?


Will clearing the codes turn off the sevice engine light too?
Yes, but it will come back on if there is another fault detected. Staying in 3rd gear should prevent P0741 from coming back though.

I get to PCM? and nothing happen I can't get it to ask me to clear codes are these directions wrong for my make amd model?
Sounds like you are doing it right. When in the diagnostic mode, HIGH fan = YES and LOW fan = NO to the prompts. Try holding the button till you get a response.

01-17-08, 12:43 PM
It worked!! No more codes!
I'll drive it in third but what is the top speed at that gear?

01-17-08, 05:15 PM
Way faster than the legal speed limit. The only problem is that you'll run a little higher RPM and burn more gas.

01-17-08, 06:12 PM
Ok that makes me feel better at least I can get it inspected when it's due.
I guess I'll do that cleaning job you recommended before and post again after that gets done.
Many many Thanks