Considering a 95 STS-

[Stormtrooper1]

I posted a topic in the STS specific forum, but it looks like all the traffic is over here,

So this is my original post-

Hi-

I'm looking at picking up a 95 STS with 178,xxx on it, 2 owner car, 2nd owner has had since 55,xxx.

The seller says the transmission shifts rough, once in a while, so they stopped driving it (they have 3 cars anyway) they think it's the transmission presser sensor. the cars fault codes are Fault codes are P0052, P0076 and P0109.

Basically I'm wondering what a good price would be for this, what it would take to fix, and if it's even worth the money? they are asking $1450.

I am looking at using it for a commuter car (sad, i know) I had a 96 Deville a few years ago and loved the car (if anyone was here back then you may remember me) and I drive a lot of highway miles to work and back and would love the comfortable ride of a cadillac again.

Thanks!

Mike.

[Cadillac Jim]

P0052 Heated Oxygen Sensor (HO2S) Heater Circuit High Voltage Bank 2 Sensor 1

P0056 Heated Oxygen Sensor (HO2S) Heater Circuit Bank 2 Sensor 2 (?)

P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

I don't have a code P0076 in my database; I'm guessing that it was a P0056.

The oxygen sensor codes may be due to a loose connector or the oxygen sensor may be bad. The MAP sensor does go bad occasionally but I had the code come up consistently at one time and found that it was just a loose connector. I have my original 12-year-old MAP sensor. However, if you rule out the connector and still get the code, it's easy to replace.

The MAP sensor is what is making the transmission shift hard. It serves the same function as the vacuum modulator in older transmissions and the result of failure is similar, but not as bad as a mechanical transmission because the computer running your transmission just changes mode and operates without the data.

Any one of these will turn on the "Check Engine" light so the car can't get an emissions inspection in any State. That's the real reason they quit driving it. Thus I would want the right of refund if the car can't get a current emissions inspection for under, say, $500. If you want to get more specific, have the car looked at by a mechanic who gives you an estimate, and make sure that the price is adjusted from appropriate KBB pricing by that amount.

[KHE]

The MAP sensor is what is making the transmission shift hard. It serves the same function as the vacuum modulator in older transmissions and the result of failure is similar, but not as bad as a mechanical transmission because the computer running your transmission just changes mode and operates without the data.

The ECM uses the MAP sensor along with the mass airflow sensor determine the proper air/fuel mixture for the engine. I do not believe it has anything to do with the trans. If the trans. is shifting hard, the line pressure may be defaulted to high due to an internal issue with the trans.

[Cadillac Jim]

When I had my MAP code, the key to knowing when it happened was hard shifting and the MIL light. Trust me, it is part of the transaxle data, as well as the DFT data. The FSM says that the PCM, which operate the transaxle as well as the DFI, says "The PCM uses the MAP sensor values as an indicator of engine load."

The 1997 FSM page 6-315, on DTC P0108, gives these actions when P0108 sets:

• PCM turns ON the SERVICE EMISSION SYSTEM message.
• PCM disables long term fuel trim.
• PCM uses a substitute MAP value based on engine RPM and throttle angle.
• PCM uses 92.2 kPa for barometric pressure.
• PCM disables Evaporative Emission (EVAP) control solenoid.
• PCM disables torque management.
• Transaxle shift adapts are maintained at current levels.
• The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
• The PCM will record operating conditions at thetime the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

If the shifting is really hard, you should suspect something else, like a loose connector on the VSS, but that will also set a code and cause other things, like a zero reading from the speedometer.

[lothos]

P076 is a transaxle pressure control code. It increases the line pressure and will cause some hard shifting.

I'm from Minnesota as well, and we don't do testing here in order to register a car. I've done some research on the P076 because my 1995 STS has the same problem. It seems like people have narrowed it down to the pcm needing to be replaced.

What part of MN are you from? I think I've seen that STS on craigslist, it looks like a good deal.

[lothos]

The P076 is slightly annoying, but you get used to it and it's very liveable. I was reading another thread on a different forum and the conclusion was that the PCM computer needs replacement. Someone swapped out the PCM from a car with the P076 into a car that didn't have the issue, and that car had the P076 problem as well.

I've been looking into getting a PCM from a junk yard, it doesn't seem like a hard fix at all. When I get more free time here this winter I'm going to see if the PCM connections can be re-soldered or fixed somehow.

I'm pretty sure this is the car he's looking at, looks pretty nice to me.

http://minneapolis.craigslist.org/cto/888972859.html

[Stormtrooper1]

Thanks for all the responses.

Lothos- you are correct that is the car i'm looking at. im in the Twin Cities Area.

If the problem is livable, I think i may have to look in to this more.

Now i jus have to find time to see it before someone else buys it!

[KHE]

The P0076 code is the reason for the harsh shifting. I would not buy the car thinking that replacement of the MAP sensor would cure the problem.