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2001 DTS on Life Support

6K views 51 replies 11 participants last post by  RippyPartsDept 
#1 ·
Gentlemen,

I have a 2001 Cadillac Deville Touring Sedan (203,000 miles) I love this car!

Here are my Current Codes:

IPM B0248 - Heat/Defrost/AC Door Range Error
IPM B0249 - Temperature Control Door #3 Inop.

PCM P0171 - Fuel Trim Lean Bank 1
PCM P0174 - " " " Bank 2
PCM P0452 - Fuel Tank Pressure Sensor Cicruit Low Voltage
PCM P0463 - Fuel Level Sensor Circuit High Voltage
PCM P1189 - Engine Oil Pressure Switch Circuit

Here are the symptoms:
- Intermittent Long Crank on start up
- Rough Idle Prone to Stalling at times
- When driving if too much throttle is given the car will stall
- Must accelerate very slowly to avoid stalling
- Combined MPG down from approx 20 MPG normal, to approx 15MPG current
- Driver Constantly worried about stalling while driving

I have tried a few things after reading posts and researching. I suspect there is a vaccum leak somewhere in the system. I have cleaned Throttle Body, I have replaced PCV, I have replaced intake blue intake gaskets on bottom on intake manifold. I am unable to locate the vaccum leak.

Do I need a smoke machine? Is there any way to locate this suspected vaccum leak? Could this be a fuel delivery problem?

Any help is appreciated!

Frustrated Caddy Owner
 
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#2 · (Edited)
Re: 2001 Caddy DTS on Life Support NEED MD!!! Help


-----------------
PCM P0171 - Fuel Trim Lean Bank 1
PCM P0174 - " " " Bank 2

Rough Idle Prone to Stalling at times
- When driving if too much throttle is given the car will stall
- Must accelerate very slowly to avoid stalling
- Combined MPG down from approx 20 MPG normal, to approx 15MPG current
- Driver Constantly worried about stalling while driving


all this is caused by a torn plenum -
the rubber bellows-looking thing - between the throttle body and intake -

they usually split on the bottom - run your finger in the groove - you will find it -

amazon.com had a "kit" put together - the plenum and the intake gaskets -

http://www.amazon.com/gp/product/B004SF3FV4/?ie=UTF8&me=ADG953YR6NRBF

there should be a "HOW-TO" either in the NorthstarPerformance forum - or the TechTips forum -
 
#5 ·
Re: 2001 Caddy DTS on Life Support NEED MD!!! Help

Gentlemen,

WE HAVE ACCELERATION!!!!

Thanks for the help, here's is what I discovered. First of all I am getting really good at removing the intake manifold lol...I've done it so many times. After close inspection the Plenum is 100% intact. I cleaned it up, looked it over, shine a flashlight on it and rubbed my hands on it. It is safe to say the Plenum is 100% in working order.

I did replace the elbow on the throttle body as y'all recommended, there WAS a hairline fracture in the plastic, good call. I also believe the Secondary Air System has been removed on this DTS. I am stationed in Yuma, AZ and they do no run emissions here, so no harm no foul. Except, I believe the secondary air system is partial cause of the vacuum leak. After messing with different tubing connected to the throttle body. I noticed the idle really steadied out when the line above the Fuel Pressure Regulator is blocked (my finger over it). I stuck a golf tee up there to keep it blocked off, i know it is a jerry rig. But the test drive was much better. There was some sensor attached also that was giving off a hissing sound intermittently (must be a leak). Does anyone know what this sensor is? It was orange in color connected to the same wires as the fuel injectors and bolted to the back bank of cylinders on the valve cover. I have No idea what that is!

I think there is still a slight vacuum leak. I can hear a hissing sound over by the power steering pump near the back side of the manifold.
After clearing the codes I am still getting a P0171 and P0174, but it is remarkably better!!! I will do more further investigation tomorrow and report the findings. Thanks for the support!

Cadillac for life!
 
#6 ·
Re: 2001 Caddy DTS on Life Support NEED MD!!! Help

Hissing sound by the back bank might be the PCV line. Check the fit in the grommet mounted in the rear cam cover. Can't recall if the '01 has a rattle can PCV valve or the metered orifice, but either way, the hose should fit tight in the grommet.

Not sure what vacuum line you plugged, but it might have been for the AIR pump check valve. There should be two, one on the rear cam cover and one up front near the W/P belt cover. Maybe there is another open vacuum line.

As for the orange hissing sensor. :noidea: A picture would be worth a thousand words.
 
#8 ·
Re: 2001 Caddy DTS on Life Support NEED MD!!! Help

There is a vaccuum line that runs from the rear of the intake manifold to the right side strut tower.

I believe there is a check valve on the line that the intake hose attaches to. I think that line runs to the heater system. Double check the line from the intake to the check valve, and the valve itself for leaks.
 
#12 ·
Gents,

The Smoke Test Reveals All! Man the smoke machine is so efficient, why have I been racking my brain trying to find this vacuum leak>? I should have used the smoke from the start. Never again will I attempt vacuum leak diagnosis with out a smoke machine!!!

The first leak I spotted with the smoke machine was from the TPS sensor, located on the Throttle Body. I removed the TPS sensor to find +200,000 miles worth of carbon buildup! My goodness was it dirty. I cleaned it up and attempted to replace the O-ring. However the O-ring was an oddly extremely thin O-ring, could not find a suitable replacement so just reused it. Then I checked the valve right above it. I think the IAC valve? or possible EGR valve? it was also extremely dirty. A little wire brushing and tightening down licked those two pesky leaks.

Then as the pressure from the smoke machine continued to build, a thin wasp of smoke came from the back on the intake manifold. I removed the intake manifol to find a cracked brittle PCV valve hose! I suspect this was the culpirt all along!!! This PCV hose was not available anywhere in Yuma, AZ good grief. It cost $56 to have delivered to the Cadillac dealership, will have it Friday. I jimmy rigged some fuel line and radiator line to connect the "rattle style" PCV valve back to the Intake Manifold. Kind of a pain due to the way the PCV hose connects way down deep in the intake manifold! It makes it impossible to get a hose clamp on there. Oh the Joys of Cadillac Maintenance!!!

After reconnecting everything and checking smoke once more...... GREAT SUCCESS!! Caddy is running like a TOP codes have all gone and SES light is gone we will see how long that lasts! LOL

Thanks for the Help Everyone!

You are right on track with the AIR sensor solenoid, that must be the orange sensor that was hissing! What affect will that have if any by essentially blocking the AIR system? Will this affect my HVAC??
 
#14 ·
The first leak I spotted with the smoke machine was from the TPS sensor, located on the Throttle Body. I removed the TPS sensor to find +200,000 miles worth of carbon buildup! My goodness was it dirty. I cleaned it up and attempted to replace the O-ring. However the O-ring was an oddly extremely thin O-ring, could not find a suitable replacement so just reused it. Then I checked the valve right above it. I think the IAC valve? or possible EGR valve? it was also extremely dirty. A little wire brushing and tightening down licked those two pesky leaks.
The TPS does not come in contact with carbon and I do not believe that there is any O ring involved. I suspect you may be talking about the IAC valve. The IAC valve is above the TPS.

Courtesy of Submariner409
P.S. This is a Seville so your air filter housing will be slightly different.
 
#15 ·
I do believe it was the TPS Sensor, it was on the side of the TB, and it was really dirty inside. I connects the the throttle plate and has a rotational peg, held on by two screws. If you look at the inside of the sensor you will see a blue o-ring.:)
 
#17 ·
Gents,

Bad News my car is still exhibiting poor gas mileage and acceleration problems. I ran the codes again and am still getting P0171 And P0174. I have avaccum leak somewhere and my smoke test did not reveal it!

Now I am also getting a new Code:

P0741 - TCC Stuck Off

Does anyone know what TCC is and how to fix P0741?
 
#20 ·
Gents,

Bad News my car is still exhibiting poor gas mileage and acceleration problems. I ran the codes again and am still getting P0171 And P0174. I have avaccum leak somewhere and my smoke test did not reveal it!

Now I am also getting a new Code:

P0741 - TCC Stuck Off

Does anyone know what TCC is and how to fix P0741?
Torque Converter Clutch. P0741 indicates the internal seal in the TCC is leaking, and as a result the TCC won't lock up past ~43 mph, resulting in 300 RPM higher engine speeds on the highway, and a decrease of about 1-2 mpg. It will cost you $1500 to fix at a good indie shop, more at a national shop. Unless you (A) have state vehicle inspections in your state or (B) are OCD about the SES light (like me :D ) You may want to consider living with the issue. Many members on here have the P0741 code and deal with the mpg decrease with no other consequences. Right Ranger?
 
#21 ·
Cadillac Luke,

Thanks, I am really starting to think this is a Transmission issue. That would explain why my DTS revs great when in park but drives like its stuck in cement when in gear. Anyone know a reputable place to buy a reman Tranny for a 2001 DTS? I am up for the challenge of pulling and replacing my self. I am really learning alot doing all this stuff my self.

This is for the bourbons and the Cadillacs!
 
#26 ·
I inspected the plenum really closely. I mean I really examined it the last time I had it off the car. It appeared to be 100% intact, maybe I should just replace it anyway. But I hate throwing parts at something and then if that doesn't fix it Im back at square one. I will re-check again this weekend and report the reults.

Rippy Parts, thanks for the infor on P0741, that seems like a really complex repair. I don't know if this shade tree mechanic is skilled enough for the job. Respect.
 
#28 ·
The plenum duct is 14 bucks, infact, just re felpro gasket your whole manifold, the cluster bomb approach with these rubber parts in an older car should cost less than 30 bucks.

For how little work it is to replace these cheap gaskets after you get the manifold off, it's not worth it to not replace them.

Also the TCC code, if you MUST get rid of it, it's going to be time consuming, expensive and net nearly zero gain. I didn't like the fact that it basically tied up my SES light leaving other potentially bad things to go unnoticed.
 
#29 ·
The plenum - at 203,000 miles, if you decide to replace it, also do the 8 intake manifold seals and do a close inspection for a cracked intake manifold hold down bolt boss.

Many pictures on this for your engine - Click my username, open the profile. left column, lower part 2 albums, 6 pages of pictures and diagrams for your engine.

RockAuto has the Dorman plenum AND intake seals for about $15 + shipping. Your car, year, engine, "intake coupling".
 
#31 ·
Thanks for the input everyone...things just seem to be getting worse. I noticed there was a change in the engine the past two days.

Normally upon startup she will idle at about 1200 RPM for 30 seconds with an electronic motor or something sounds like it is pressurizing air before settling down and dropping to around 700 RPM. Does anyone know what causes this air pressurizing sound on startup?

This morning the air pressurizing sounds like it was struggling hard, this caused my car to run extremely rough and die. I could not even drive into work today, had to get a ride.
 
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