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Sporadic SES light and exotic codes - friend's 2004 DTS

27K views 184 replies 10 participants last post by  Ranger 
#1 · (Edited)
Here I was thinking my Cadillac troubles are over but ... A friend owns a '04 Deville DTS and was complaining to me about the SES light coming on and off randomly. He asked me to have a look since I went through so much trouble with my old Seville. During a test drive I didn't notice anything strange but a rough idle with slightly elevated rpm that totally goes away the warmer the engine got. The Deville also has abyssal gas mileage of below 13 MPG. After a couple of miles the SES light indeed came on and stayed on until we parked the car. 10 minutes later we got back in the car and drove the same route back with the light not coming on at any point in time.

Strangely, it is not throwing any code that can be read out with the internal code reader but two codes concerning the front seat adjustment motor. One remains of my old Seville was an external code reader that threw out the following:

Trouble Code: P0174
ABSLT TPS(%): 14.5
ENG SPEED(RPM): 2027
CALC LOAD(%): 50.2
MAF(gr/S): 29.45
MAP(KPa): 71.0
COOLANT(°C): 94
IAT(°C): 27
IGN ADV(°): 39.0
SECOND AIR: ATMOS
ST FTRM1(%): 8.6
ST FTRM2(%): 0.0
LT FTRM1(%): 21.1
LT FTRM2(%): 24.2
VEH SPEED(KPH): 78
FUEL SYS 1: CLSD
FUEL SYS 2: CLSD

After some quick research through this board, it could be a vacuum issue. We did a quick check of all apparent vacuum lines and the only one showing clear signs of degradation is the one circled yellow in the picture below. The rubber hose part is cracked by an inch (on the bottom) and the hole connection is very shaky and loose.

Auto part Fuel line Automotive fuel system Engine Vehicle


Unfortunately, I have no idea what that particular part is or what it's supposed to do - and therefore does not know whether this could be a/the cause for the SES light. I also read here on the boards that I should just get a can with some carb cleaner or so, carefully spray the vacuum lines, and listen for rpm changes to isolate any vacuum leaks. I'd like t do that but was unable to find a picture or diagram clearly marking all candidate spots. Is such a treasure hidden deeply somewhere?

EDIT: I didn't notice this at first with the code reader: P0174 is marked as "pending" while P0171 was "confirmed". Don't know how that translates into the H/C marks with the in-dash reader.
 
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#69 ·
A spongy brake pedal sounds like air in the lines that needs to be bleed. A "whine" could be a vacuum leak (depending on how you describe it). After listening to the Youtube, it does sound a bit like vacuum. I assume that noise was when you step on the brake?
 
#72 ·
The MC, pads, and rotors are new and were put in end of January, 2013. The look more than fine. The only "bad" thing that I can see is a somewhat squished bleeder valve screw. Could this be an issue? Is it acceptable to just replace this screw, untighten it, and bleed air+air by stepping on the pedal; then tighten and hope for the best?
 
#73 ·
If the bleeder valve is not sealing properly, yes that could be an issue, but if that where the case and it was letting air into the system, I would also expect it to be leaking when under pressure (brake applications). Is the back of the caliper wet? You can replace it if need be if you can get it out without breaking it.
 
#74 ·
Cool! You found the problem. The brake power booster is broken. Among other problems it leaks, this is the sound as it's ingesting air under intake manifold vacuum. Your source of a bad brake pedal and sporadic fuel injection lean codes is the same thing. Remove and replace. I haven't done one on a Deville but they can be a difficult job due to the under dash accessibility of the fasteners and switches. There's a black plug spacer between the master cylinder and the booster push rod, it will pop out from a spring if the pedal is depress with the master cylinder removed. Pop it out on purpose with a helper there or a rag to catch it so it doesn't get lost or overlooked upon reassembly.

Vernon
 
#75 ·
@Ranger: It is very hard to tell - >100F yesterday. It appears to leak a small amount of fluid around the edges of the broken bleeder valve - at least there is some semi-wet residue. The MC is more or less holding it's level as far as I have seen in the short hours having the car. After inquiring closely, I learned that the screw fell out once when the tires were rotated a week ago but no one knows whether the system was bled afterwards.

@Manic: Thank you! Are you saying that the system is leaking (vacuum) air or fluid? Conditions of the brakes at the moment: The MC was replaced in January by a dealership mechanic, all pads and rotors are basically new, all hoses inspected for damage. I'll go over in a little bit an try to pin-point the source of the whine, alongside with the bleeding and the plenum check. I'd assume that the brake booster has a vacuum line attached and that I am supposed to inspect this line as well for any potential leaks? I know where the booster is located (big black cylinder right behind the MC), is the vacuum line easy to follow or is its view obstructed by some other parts of the engine?

I still have hope that it's just that nasty bleeder screw after I learned yesterday night that it physically fell out of its socket.
 
#76 ·
CD I'm saying that the booster is leaking vacuum air. Inside the big round canister is a rubber diaphragm, engine vacuum is maintained on the front side and when you push the pedal rod a mechanism applies the force of the vacuum pulling on the diaphragm to increase the pressure against the master cylinder hydraulic piston, hence "power brakes". The linkage or push-rod goes through the center of the diaphragm with a seal to keep the vacuum from escaping. This seal has failed, it may be leaking all the time but when you push on the brake pedal the seal is shifted to a point where it really leaks. This is when you hear the noise of air pushing through this defective seal. They can whistle, howl, whine, roar, etc. at random. Having a stiffer than normal pedal in another symptom as the amount of power assisting vacuum is constantly being bled off through the leak. The vacuum is plumbed from the intake manifold itself, it's the large rubber hose just above and behind the throttle body. The check valve is located in the plastic fitting on the booster the hose is on, it holds vacuum when the pressure in the intake is high. There is normally enough vacuum stored in the booster for 3 stops without being replenished by intake vacuum. Air is removed from the booster and it stays that way. Vacuum itself is used for assist and air is not, so there is no significant air flow into the intake without a leak. The fuel injection will set a lean code when in closed loop the leak is bad enough for enough time, like hot engine at a long light or at a drive through window with the car in gear.

As for the fluid leak, see if you can dry it with brake clean then go for a drive or hold the pedal hard for a while. Watched points never boil and drives seem to work better than hold and wait on slow leaks If it's leaking you'll have to attempt to replace the bleeder. New ones are available at the parts store. If you can't get it out without destroying the threads in the caliper just replace the whole caliper. After the repair bleed the air out at that wheel.

Vernon
 
#77 ·
Good morning, a little update: I bled the system according to the procedure on alldatadiy. Rear was just perfect but front was horrible. After fiddling the broken bleeder screw out, the liquid shooting in my pan was jet black, oily, and had dirt/metal particles in it. After 5 cycles, it cleared up. I also cleaned and lubricated all caliper slide bolts and the non-braking surface tips of the pads (where they touch the metal spring inlets). He has an ACDelco Advantage rotor and pad set in the back and Raybestos Pro in the front but I don't think that can cause uneven braking or problems.

The test drive was just right, at the first hard stop from 45 to 5 mph, we almost hit the dash. The pedal travel is now reduced to one third of its way, no whining at all, and the fluid system is tight now. I will, however, definitely have that brake booster checked out by a pro at the next service - the whine was there and noticeable enough to be captured on my crappy phone.

Edit: Manic: I also ran a set of your procedure with MAF, etc. Regardless of being hot or almost cold, the car does not run anywhere close to smooth when I disconnect the MAF. You mentioned a cleaning procedure for the other sensor (MAP) but I was unable to locate it in the Deville or Tech section.
 
#78 ·
Re: sporadic SES light and exotic codes

This is a heads-up for anyone driving these FWD (and any other type) of vehicle: Brake fluid simply LOVES moisture. It is highly recommended to perform a complete brake fluid exchange every 5 years or so. A simple pressure bleed rig is not expensive and 2 people can do the job in the driveway in an hour or so. Or, you can take advantage of a (in our case) GM dealer "Fluids exchange special" in which they hit you for ~$400 and completely change all P/S, transmission, coolant and brake fluids. You get the latest and greatest GM fluids as well as a written invoice in case of problems later. It's all normal preventive maintenance anyway.
 
#80 ·
The Deville is totally turning Cadillac on me: with every piece repaired, two others fail. When checking for new codes, this showed up:

PCM 1811 H - Maximum Adapt and Long Shift

I was asking whether he had issues shifting gears and, indeed, there was one day when switching from first to second was not smooth but noticeable. Is there anything I need/should/can do besides checking the fluid level and consistency?

On the front driver control bars, there is flaky green/blue goo that seems to be coming from one big rubber booth (I miss out on the correct English term here, maybe "pressure sleeve?") just over it.

On a side note: I have performed some more routine maintenance such as changing the air filter to WIX. The car sounds much more throaty now (like a chain smoker) when stepping on the gas. Is that normal?
 
#81 ·
On the front driver control bars, there is flaky green/blue goo that seems to be coming from one big rubber booth (I miss out on the correct English term here, maybe "pressure sleeve?") just over it.
That sounds like CV joint grease which means a ripped CV joint boot.


On a side note: I have performed some more routine maintenance such as changing the air filter to WIX. The car sounds much more throaty now (like a chain smoker) when stepping on the gas. Is that normal?
I would not expect that to change the exhaust note.
 
#83 ·
c_d said:
I have consulted the alikes of Eric the Car Guy at youtube (don't laugh) and the take away was an axle only being priced around $50 so it's actually cheaper and less problematic to swap the whole part.
Good luck finding a $50 axel, and good luck having it last more than 6 months.

It's not the exhaust sounding throaty, it is coming from the left driver's side engine compartment when stepping on the gas.
Induction noise from your vacuum leak.


outrageously expensive repair for something called a coolant crossover
Long, tedious, PITA of a job. Over $1,000 at a dealer.

it's still in need of the full plenum repair (instead of the quick fix)
There is no quick fix for a torn plenum, it has to be replaced.

the front passengers side started to rattle when going through pot holes/speed bumps.
Possibly sway bar links/bushings.

Some things are left undiagnosed yet, such as the liquid bubbleling sound at strong accelerations: it's like someone gurgeling listerine while simultaneously having a full fish tank in the engine compartment.
Air in the cooling system. Potentially a very bad sign. Is it running hot?
 
#84 ·
Good luck finding a $50 axel, and good luck having it last more than 6 months.
I only have access to O'reilleys, Autozone, etc. Rockauto is quoting between $44 for a "CARDONE Select Constant Velocity Drive Axle" and $600 for ACDELCO 20984613; with the specific part number mentioned by alldatadyi being in wholesale closeout.

Induction noise from your vacuum leak.
I'll check for that, too.

Possibly sway bar links/bushings.
Thanks, Moist. I educate myself and check.

Long, tedious, PITA of a job. Over $1,000 at a dealer.
Air in the cooling system. Potentially a very bad sign. Is it running hot?
He had it done in February, for $640 in labour and roughly $210 in parts. We were told the coolant was changed at this point. Sometimes (maybe once a month) the temp needle is a millimeter higher than usual but usually its glued to the 12 o'clock position. I discounted that to the car being operated at >95F ambient temperature.

The shop we go to is usually very good (we finally found something close to trustworthy in SA, TX) but they have bad days - I found a rogue screwdriver once. Can it be that the coolant was not filled properly?
 
#89 ·
Moist, you jinxed it - all your fault! :eek: We took the Deville to go to downtown again. While we were discussing what I have read on these boards, a thunderstorm came by. During some heavy rain and just after passing through a huge puddle, the temperature rose from 12:00 o'clock to 1p in about 30 seconds. After that at idling or low speed, the temp was rising up until a tad after 1p but going down rapidly (10 seconds) to 12p at highway speeds. The car stood in a parking lot for about 2 hours, the temperature did not rise beyond 12 at back roads and interstate until ... we hit the rain. Same game, quick increases and decreases.

I will check the purge line tomorrow. Anything else that comes into mind (beyond checking coolant level)?
 
#90 ·
Ok, bad news as usual. I disconnected the purge line - some previous owner used stop leak and I had a lot if red coppery flaky stuff in there. The purge line was not entirely blocked but just had a little resistance. I cleaned it anyway but what I found during the process was a deliberately cut coolant level sensor wire with the part to the computer being shortened. I'll replace the coolant in a little bit and see how it's performing.
 
#92 ·
According to Compnine, it's the following Vehicle: "DEVILLE TOURING 4 DR Year: 2004 Build Date: Unk." So I hope it's not as catastrophic as you suspect.

I really *hope* it's that coolant crossover issue of the past because I remember he had an extensive repair just after he bought it because it was leaking like hell. We brought the car to our mechanic together and I remember the mech. saying "I smell coolant" while he was opening the hood." The wire itself was expertly taped away UNDER the coolant surge canister and I would not have found it if I wouldn't have studied a thread on there boards about a stuck floating element (with pictures). He had this repair done in January and I replaced maybe half a quart (liter) of coolant to the max cold line today. The car drove around 2k miles since the repair, mostly inner-city stop-and-go.
 
#96 ·
I followed the procedure cleaning the purge line again yesterday as I was not fully convinced about the success of my first try. Despite the two rubber hoses and plastic line being reasonable clean, the bolt only appeared to be. I cannot stress this enough: follow the advise given on this board and use a generously sized tool to work the bolt. I ended up using the straw from a brake cleaner can to pre-clean. After a couple of rounds, and without warning, a steady and sizable stream of coolant evacuated.

What is commonly referring to steady and sizable - at the connector of the coolant surge tank - is: picture a small tap in your garden house. Not just dripping or a small stream, a real flow of approximately 1/2 cup per second extending the whole diameter of the purge line. Be careful with trying to measure at the hollow bolt whose diameter is much smaller (higher pressure) and hard to capture the coolant: spilling is imminent.

I also did some electrical work by reconnecting the coolant level sensor. Strangely, an alternating check coolant / check oil came up. I immediately checked the oil to find it in the perfect spot as well as still fully intact. The oil notification went away after 10 minutes of additional driving, the coolant seems to be here to stay. Gently tapping the floater did not seem to work and it *appears* it is floating. I suspect the sensor itself being broken and that is very inconvenient. I still have my bubbling liquid sounds but at least I am imagining they are much shorter now and do sound different. I'll follow the procedure of giving it 2-3 days and re-assess (while frequently checking the coolant).

On another thought: I was debating connecting my fluid extraction unit to the end of the purge line that connects to the surge tank. That may be a spill free and extremely quick way of assessing the condition of the purge line. Another though was to get a rubber hose that is transparent as well as heat resistant to enable a visual inspection without fiddling around with tools and spillage.
 
#97 ·
On another thought: I was debating connecting my fluid extraction unit to the end of the purge line that connects to the surge tank. That may be a spill free and extremely quick way of assessing the condition of the purge line. Another though was to get a rubber hose that is transparent as well as heat resistant to enable a visual inspection without fiddling around with tools and spillage.
The easiest way is to just pull the hose, remove the surge tank cap and stick it in the the tank. Clean, easy and quick.
 
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