94 Eldo P071, P071, P095

[Ion]

Hi all...

Hope to get some direction re: these error codes and how to best diagnose their origin and repair. Since the P070 is intermittent TPS signal, will replacing the TPS sensor remedy that problem? Re: the P071, intermittent MAP signal, will replacing MAP sensor fix the problem? I'm assuming the P095 engine stall error code will disappear when the previous two are fixed.

[Cadillac Jim]

Very often an intermittent sensor performance code means that the connector is loose or dirty. The TPM and MAP sensors don't go bad very often. Look at the wiring first.

[Ion]

Hope you're right, Jim! I'll check it out in the am and let you know what I find.

I neglected to state why I looked at the error codes in the first place...the motor bucks, hesitates and sometimes just dies. If I floor the gas pedal, there is a delay before the motor responds. Not quite as evident if I accelerate slowly. Also, while rolling down the street when this behavior begins, I will accelerate, have no motor response, then hear it rev up a great deal, without the transmission engaging. Fun stuff!

[Logan]

1994? There were some goofy ECM's floating around that era.

2 pretty hard codes. Having both go at the same time..unlikely. If original ECM/PCM, it is right at that age for failure.

Is it worse after 15-20 minutes of driving?

If so, may be warm/hot ECM failure. Drop down the ECM/PCM and slap around the case as the car idles. Any 'check engine' or stall issues indicate a bad/failed ECM/PCM. Screwdriver handle works great for this...tap testing.

That being said, I think the MAP and the TPS share the same ground. Would have to look it up..

[coolnesss]

\ If I floor the gas pedal, there is a delay before the motor responds. \

Speaking of which - I haven't seen any WOT references lately on this board - has everyone lightened their feet for the coming winter???

[Texas Jim]

Speaking of which - I haven't seen any WOT references lately on this board - has everyone lightened their feet for the coming winter???

Not quite.... This may not be the kind of WOT you were talking about, but ....

Got a chance to test my Performance Sedan against a regular DTS the other day. Stopped at a light beside a regular 2006 / 2008 DTS. ( I can't tell the difference in the year models ) Wasn't looking for a race.

The light turned.. I took off fairly briskly. Heard some tire squeal and he came blowing around me. Surprised me. At the next light he motioned with his hand to "GO". I nodded ok. As I was looking at him, the light turned and he jumped me about a half car out of the hole. As mine hit about 3500 / 4000 RPM... started walking around him. By 80 MPH, was about 2 car lengths ahead of him. The next light... he was laughing and shaking his head "NO"

[Ion]

1994? There were some goofy ECM's floating around that era.

2 pretty hard codes. Having both go at the same time..unlikely. If original ECM/PCM, it is right at that age for failure.

Is it worse after 15-20 minutes of driving?

If so, may be warm/hot ECM failure. Drop down the ECM/PCM and slap around the case as the car idles. Any 'check engine' or stall issues indicate a bad/failed ECM/PCM. Screwdriver handle works great for this...tap testing.

That being said, I think the MAP and the TPS share the same ground. Would have to look it up..

The PCM (re-man), ignition control mod. and EGR were replaced in '01. The condition has become so bad, that I don't trust the car on the road anymore, but...previously it seemed that after the initial startup and say, trip to the bank, where it was parked and sat for awhile, the subsequent startup and drive went significantly better...almost no sign of any problem.

Re: PCM...where is it? I paid a local GM shop to rape me when it was replaced in '01.

[Ion]

Just read in another forum where a guy with a '94 was getting the same error codes had replaced the TPS, had no improvement, then was advised to go back to "basics" and focus on the mechanical. He replaced plugs AND wires and problem went away. I recently replaced plugs with recommended Delco plugs but did not replace wires. I think I'm going to do that today and see if I'm as fortunate as that previous poster.

[Logan]

The PCM is the large silver box (reman PCM's sometimes are black) mounted behind the glove box.

[Cadillac Jim]

On a 1994 ETC, isn't the PCM under the air cleaner element behind the driver's side headlight? Or did they move the PCM in teh 1994-1995 updates?

[jackc]

.....

[Ion]

UPDATE:

I replaced all plug wires, inspected all sensor connections, removed glovebox to access PCM (dinged it a few times as suggested), then went out for a test ride. Aside from the airbag-related error code due to disconnecting it's wire harness on the glovebox, it seems like the problems are only a fraction of what they were. A slight hesitation upon acceleration, but no bucking or complete stalling. Maybe it's just an anomaly? I still have not re-installed the glovebox or re-connected the wire harnesses. I'll do all this tomorrow, as well as test drive again and report back with results.

Note: after replacing all plug wires, but BEFORE removing glovebox, the car still ran like crap! The major improvement occured after first test run and after glovebox and all it's wire harnesses were removed. Go figure?

[BodybyFisher]

IT could be a bad ground or harness connection at the PCM, disconnect the wiring harness at the PCM and plug it in and out a few times to clean the contacts. Its still possible that you have a bad PCM.

[Logan]

Maybe a bad PCM. I have seen them stuffed (forced) back in the original position with with harness so stresed it creates a load on the internal circuit board. The PCM fails.

Over a 5 year span. The PCM fails. Some scan tool readings have shown coolant 400F + readings. Not possible. Bad PCM.

The 1994 PCM is behind the glove box. 1996 OBDII moved it out to the intake air duct.

Could also be pin oxidation. Plugging in and out can 'clean' the pins.

There were some goofy 1994 PCM's floating around. There was a GM TSB on those..no recall. And they were for a false MAP error.

[Ion]

FOLLOWUP #2

BAD NEWS!

Yesterday's second test drive that yeilded noticibly better results after disconnecting wire harnesses connected to glovebox and "dinking" the PCM WERE an anomaly! This morning's test run (nothing has changed from the way I left it last night) was back to the same old crappy acceleration hesitation, drop-off, bucking etc.

I'm going to replace the PCM and see what hapens. Any referrals on a reliable remanufactured PCM place?

[Ion]

I just ordered a PCM through a local Carquest. Same part # as the current one. Should arrive thursday morning. Will report back with results.

[Ion]

UPDATE:

My Carquest people suggested that since the OBD had P071 and P070 errors, that I attack those issues before replacing the PCM because doing so while still having a faulty MAP or TPS might cause damage to a new PCM. So...I replaced the TPS, cleaned the throttle body, plugged in my old PCM and re-connected the battery. No improvement whatsoever! Tomorrow, when the MAP sensor arrives, I'll replace it and see what happens.

Havin' some fun!

I just ordered a PCM through a local Carquest. Same part # as the current one. Should arrive thursday morning. Will report back with results.

[kad3338]

UPDATE:

My Carquest people suggested that since the OBD had P071 and P070 errors, that I attack those issues before replacing the PCM because doing so while still having a faulty MAP or TPS might cause damage to a new PCM. So...I replaced the TPS, cleaned the throttle body, plugged in my old PCM and re-connected the battery. No improvement whatsoever! Tomorrow, when the MAP sensor arrives, I'll replace it and see what happens.

Havin' some fun!

I just ordered a PCM through a local Carquest. Same part # as the current one. Should arrive thursday morning. Will report back with results.

Hey, I'm experiencing the same thing as you with my 95 Deville w/4.9 and have yet to resolve the P071. So far I've replaced the PCM twice (one new, other used off ebay), R&R entire throttle body and swapped out MAP's with no improvement. This weekend I'm planning on looking for vacuum leaks and checking grounds. Also checking continuity from MAP to PCM. This code is a *smurf*! Not sure if your new MAP will make a diference, didn't for me. I'll post back if I have any luck.

[Ion]

Hey, I'm experiencing the same thing as you with my 95 Deville w/4.9 and have yet to resolve the P071. So far I've replaced the PCM twice (one new, other used off ebay), R&R entire throttle body and swapped out MAP's with no improvement. This weekend I'm planning on looking for vacuum leaks and checking grounds. Also checking continuity from MAP to PCM. This code is a *smurf*! Not sure if your new MAP will make a diference, didn't for me. I'll post back if I have any luck.

I think if I go through the new MAP and PCM and still have issues, I'll throw in the towel and bring it to the local Caddie guru. There's only so much a non-mechanic-mortal can handle!

Do let me know what you discover with your issues.

[Ion]

UPDATE:

After replacing the MAP sensor and torquing the cover torx heads down properly, the problem, at this juncture, seems to be SOLVED! Hopefully you won't hear back from me regarding this issue. If not, CASE CLOSED!