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00 DTS lambo white, eibachs, 2011 CTS-V wheels
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163 Posts
Discussion Starter #1
hey guys, about 3 or 4 weeks ago i was heading to work and while on the highway i noticed the gears started to shift harder, then when i finally started driving local it got worse, so when i finally parked the car i put the car in park and it slammed into it, then i tried it in reverse and drive again and would still slam into the gears, only time it wouldnt is if i would put it in 1 or 2 while still parked.. i checked the trans oil while on and in park and noticed it needed a quart of oil, so turned it off and left it parked, then the next morning when i went to leave the car was perfectly fine as if nothing ever happened, so i i added the quart of oil that it needed and figured it might of been due to low oil.

well last night while heading to work, again the samething happened, with the gears slamming after driving it for about 10 minutes on the highway.. and in the morning again the car was fine with no issues and have drove it all day today and still no issues whatsover, i checked the oil and it was perfectly fine..

when i first bought the dts it had about 78k miles and i never changed the tranny oil, and it now has 92k (ive always been afraid of having tranny oils replaced including filter because of the whole story about the tranny sometimes getting worse after an oil change when already bad)

(by the way is that even true ? i've heard this from a couple of mechanics, that have said that if the tranny oil hasnt been replaced or ever replaced to not change it and continue using the one it already has, because sometimes its been known for the tranny to get worse, is this just a myth?)

would it be possible that the filter is dirty? and if dirty then how come the tranny is fine the next day?

also i hope i dont sound like a retard but both times that this happened to me it was raining, and just to mention my air deflector flew off about 2 or 3 months ago, would the water maybe have something to do with an electrical connection, i've tried searching around to see if anyone with a deville has had a similar problem b ut no luck so far, oh and also i checked for codes but nothing for the tranny came up, only these which all said they were history..

C1284 - Lateral Accelerometer Sensor Bias Malfunction


U1128 - Loss of Communications with IRC


B1750 - Driver Seat Rear Down Switch Circuit Malfunction


B1820 - Driver Recline Rearward Switch Circuit Malfunction


B1860 - Driver Lumbar Vert Sensor Circuit Malfunction


B1875 - Driver Belt Tower Down Switch Circuit Malfunction


P1122 - Throttle Position (TP) Sensor Circuit Intermittent Low Voltage


B3055 - Key Not Present


B1004 - Keep Alive Memory (KAM)

u1112 - Loss of Serial Communications for Class 2 Devices
 

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99STS,2004 Jeep Liberty Renegade,98 Deville RIP
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1,054 Posts
It sounds like you did all the right things, checking codes, oil etc... I think you are on to the right idea for harsh shifting,, the rain may have a factor, I have posted for you a harsh shift grid, look at the very bottom of it.. also, if on your DIC the transmission comes up with 100% then the tranny is ok, although it should not have been down a quart.. you may have a leak somewhere.

--------------------------------------------------------------------------------

Harsh Shifts
Checks
Causes

DEFINITION: High Line Pressure

Actuator Feed Limit Valve
Stuck open

Calibrations
Not updated or incorrect platform

Checkballs
Missing

Final Drive Internal Gear Snap Ring
Missing

PCS Feed Valve
Stuck

Pressure Control Solenoid (PCS)
Failed OFF, intermittent short
Loose connector

Pressure Reg. Boost Valve
Stuck open

Pressure Reg. Valve
Stuck at high torque signal due to undersized bore, sediment or Pressure Control Solenoid failure

TFP Val. Position Sw.
Loose connector

Transmission Wiring Harness
Loose connection at vehicle harness
 

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99STS,2004 Jeep Liberty Renegade,98 Deville RIP
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1,054 Posts
One thing I should mention about the above, they do not follow in a priority order, like most of the GM flow charts.
 

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00 DTS lambo white, eibachs, 2011 CTS-V wheels
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163 Posts
Discussion Starter #4
would it also be weird though that if it were the transmission wiring harness loose, that it didn't throw a code?
 

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99STS,2004 Jeep Liberty Renegade,98 Deville RIP
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1,054 Posts
I think the fact that its raining when this happens is too much of a coincidence, the rain may be hitting the connector and causing a short or even a high impedience so when it dries everything goes back to normal. I know on my STS when its cold and damp, my speed limited to 90mph comes on but in summer it never does. A tranny shop may be able to narrow it down further for you.
 

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2003 DeVille
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4 Posts
Your car is an automatic tranny right? Because my DeVille has been putting me through it with the erratic idling and "self-acceleration" I'll call it for now, and it's an automatic. I have replaced one of the crankshaft sensors, only to find it running crappy again a week later. Now I have 5 codes that come up and 2 are the crankshaft sensors (A & B), and 2 are the LOW idle speed sensor and the HIGH idle speed sensor.
This explains my car's tendency over the past 8 months or so to die every so often when going very low speeds-like under 10 mph. It also explains the reason why it idles high, so high that at times I've put 2 feet on brake at redlights just for added safety, because if I let off the brakes at all, she's gonna plow into the car in front of me. It has gone from 0-38 mph from a complete stop COMPLETELY on it's own-without me touching the gas once. I kid you not and this seems outlandish to me.
Anyway, point is we might be having the same type of issue but maybe not. My car has done what you've described, that's why I'm interested. My car is still top notch and doesn't run like this All of the time, but it's becoming more and more a problem in hardly anytime at all. I need a solution.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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87,094 Posts
Mrspriss, You might try cleaning the TB. How many miles on it? Has it ever been cleaned? Always change both CKP sensors. You may still have one of the old ones in the car.
 

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2003 DeVille
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4 Posts
It has 87k miles and I don't know if TB has ever been changed or not. How do I know?
Now, by CKP are you referring to the crankshaft position sensors? Ironically, I did replace one (I forget now if it was the top or bottom) about 3 months ago. But are these supposed to be handled as a pair? If so, I'm unaware and only one was replaced. But I am 26 year old girly girl so I don't think that's something I'm required to know either. So in regards to your statement, yes, one of the sensors is still in place. Thank you for your advice and pointing me in the right direction.

Now since my last post I have now replaced fuel filter, air filter (irrelevant to issue), and spark plugs. I just got the car back from putting the plugs on it last night so I haven't really had a chance to run it yet.


My main complaint right now is the low idling problem. It's idling so low at red lights and stop signs, that won't even stay running. Now I don't know what the ideal RPM would be for an idle car but mine is giving an RPM reading of about 450 RPM when it's doing its lil dying at every corner thing. Things like the AC and the headlights seem to contribute to the RPM's going down strangely enough.

***When it's not idling low and frequent dying, it could be idling high and giving off an idle reading of 1100-1275MPH. When it is running high like this it just accelerates kind of on it's own and it's very strong. I gotta be careful to handle that brake and not let my foot slip off at all because it's such a strong force that even a slight release of the brake will allow that car to just plow forward.

So there's my status and thanks for all the tips and advice. I might be a girl but I take great interest in my caddy and want to learn and do as much as I can for myself with it for more reasons than one.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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87,094 Posts
A girly girl? And you're changing CKP (Crankshaft Position Sensors)? :worship: Yes, they should be changed in pairs. The idea is if one went the other may not be far behind and as long as you wen through the trouble to get to one, might as well do both.

You don't change the TB. You clean it. Pull the intake ducting and with the engine off open the throttle plate wide open. If the backside of the throttle plate and bore are all carboned up, get some TB cleaner, a rag and an old toothbrush and clean it till the carbon is gone. Normal idle is 650.
 

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2003 DeVille
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4 Posts
LOL, noooooo... I didn't change the crankshaft sensor, I should've said I had it changed I guess. Anyway, You just started speaking a-whole-nother language when you gave those instructions just now. Aside from that, it's been doing very well with not dying on me, EXCEPT today one time when I was kinda cruising at about 35-40 mph and all of a sudden it died on me. That still has me trippin out but I don't know what it is due to. I just don't have the kind of money this car deserves to have put into it to guarantee its gonna run right.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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87,094 Posts
OK, well in that case I have to retract the :worship:.

If it died while you where driving, I would suspect the other CKP sensor. A dirty TB won't cause that.
 

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2003 DeVille
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4 Posts
Thanks for the tip. I'd have NEVER guessed in a million years, and do you know that there are a million a** holes out here in Sacramento still trying to take my "anywhere from $80-$210 for that car" money for a freakin diagnostic just to tell me WHAT the problem is before it's even touched. So things like this really benefit me. ;o):highfive:
 

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1992 Sedan Deville, 1984 Lincoln Town Car
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759 Posts
I think it's more like a billion of these types of obnoxious rip-off artists. Especially when you are a customer like you (and me) of the lady kind. In contrast tho' these Caddy-loving forum guys and gals are all real class acts. Gotta love 'em.
 

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00 DTS lambo white, eibachs, 2011 CTS-V wheels
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163 Posts
Discussion Starter #15
ok fellas, turns out it was my TPS, pretty embarassing, but definitely better then a new tranny lol, thanks for the help guys
 
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