[nlong1024]

I just bought a 91 Cadillac Seville with 68,000 miles on it. Per the previous owner the car had been sitting for several years. I am having a couple of problems with it and am wanting some advice or direction on what I should do to fix it. Here's the deal....

There are some issues with it staying running once you start it up... It turns over will idle high (1500-2500 RPM's) and some times sputter and then turns off. Other times it will start, idle high, if you pump the break a few times the idle goes down to about 650-750... and then it will drive fine. While driving and watching the center screen I notice the RPM Will drop down to 0 while driving and then I get the message, "Set Timing Mode".... Sometimes I get the message before the RPM's drop, sometimes I don't and then the car will die out completly. Usually when going to restart the car it will idle hard, and high, and I've noticed the accelerator pedal kind of bounces a little bit. It seems like it's trying to keep it from dying on it's own, but the RPM will read 2000 one minute then 0 the next yet the car will still be running. ANY IDEA WHAT THIS COULD BE OR WHERE I SHOULD START?????

 

[nlong1024]

I just bought a 91 Cadillac Seville with 68,000 miles on it. Per the previous owner the car had been sitting for several years. I am having a couple of problems with it and am wanting some advice or direction on what I should do to fix it. Here's the deal....

There are some issues with it staying running once you start it up... It turns over will idle high (1500-2500 RPM's) and some times sputter and then turns off. Other times it will start, idle high, if you pump the break a few times the idle goes down to about 650-750... and then it will drive fine. While driving and watching the center screen I notice the RPM Will drop down to 0 while driving and then I get the message, "Set Timing Mode".... Sometimes I get the message before the RPM's drop, sometimes I don't and then the car will die out completly. Usually when going to restart the car it will idle hard, and high, and I've noticed the accelerator pedal
kind of bounces a little bit. It seems like it's trying to keep it from dying on it's own, but the RPM will read 2000 one minute then 0 the next yet the car will still be running. ANY IDEA WHAT THIS COULD BE OR WHERE I SHOULD START?????


I also just went and pulled the codes now, and I'm getting the following...

E014~Shorted Coolant Temp Sensor
E015~Open Coolant Temp Sensor Signal
E016~Voltage out of range
E022~Open TPS Signal
E023~Electronic Spark Timing (EST) Signal Problem (EGR)

Can anyone give me some advice on what to do and where to start?

 

[Dave S Texas]

Replace the coolant temp sensor. That should take care of 14/15. 16 is a generator voltage problem. 22 is, most probably, a wire-connection problem. Check for the plug being connected properly to the TPS. 23 may be similar...faulty connection to the Distributor. Do you know how to access the Parameters in the computer diagnostics?

 

[nlong1024]

Thank you I'm going to try out your first suggestion as soon as I jump off of here...

I do not know how to check the parameters... Do you have that info?

 

[Dave S Texas]

I do not know how to check the parameters... Do you have that info?
******************************
This is something you should have knowledge of. This part of the computer is very helpful in assessing the performance of the various sensors. I strongly suggest you purchase a Cadillac Factory Service manual for your vehicle. There are many used '91 Seville manuals for sale on ebay. The FSM is an essential tool for anyone who works on their own car. The small price is paid-back with the first problem you fix using the information your Cadillac FSM gives you.

 

[nlong1024]

Will do, much appreciated! Thank you!

 

[Arkisto]

Hi, and greetings from sunny Helsinki, Finland.

I'm having similar problems with my 1992 STS 4,9l.

It started dying on me on while driving or standing on traffic lights. At first it started quite fine a couple of times, and worked properly after restart.

Then one time it did not start and there was "SET TIMING MODE" and "ENGINE COOLANT HOT" and number "5" on the screen, and the temperature warnig light was lit. Engine was in normal temperature - below +90°C. Waited a bit and then it worked alright - for a while. The same happened again once before I was home, and "IDLE ENGINE" appeared on the screen. There where also some fault-codes on the screen but they all seemed to have something to do with ECC.

"SET TIMING MODE" should appear when one puts in a jumper cable connecting two slots of the ALDL-connector - there is no jumper cable there.

This fault comes and goes, and while it is active, following other symptoms also appear;

1. EEC does not function at all - not even vent. At first it stood "LOW REFRIDGERANT" on the screen, now it only works on "ECON" even when the car otherwise works. The system has pressure - it was checked manually, so there are no leaks.

2. No speedometer-readings.

3. When on "OD", there seems to be only gear #3 in use - similar as in "3". On "2" there is only gear #2. "R" works properly. On "1" there is gear #2

4. 3500rpm when "SET TIMING MODE" and "ENGINE COOLANT HOT"

I read somewhere that a faulty cluster might be the reason for this - ordered a new used one from e-bay - no change in symptoms.

I checked the codes, at first this was the reading;
- EO14 History (Shorted coolant sensor circuit)
- EO16 History (Voltage out of range)
- EO22 History (Open TPS-circuit)
- EO47 History (BCM-PCM data problem)
- IO52 History (Keep Alive Memory Error)
- AO11 Current (High Side Temperature Sensor Circuit)
- AO47 Current (Low Refrigerant Charge)
- AO50 Current (HVAC - Coolant Temperature Too High)
- AO12 History (Low Side Temperature Sensor Circuit)
- AO15 History (Sun Load Sensor Circuit)
- AO37 History (Loss of Instrument Panel Cluster Data)
- RO61 History (SIR Indicator Circuit Failure)
Then came "NO ECM CODES", and it all started again.

I tried to empty the code-memory, but it did not seem to be successful, so I disconnected the PCM for a couple of minutes, and after that I got these;
- EO52 History (PCM Memory reset)
- IO52 History (Keep Alive Memory Error)
- AO11 Current (High Side Temperature Sensor Circuit)
- AO47 Current (Low Refrigerant Charge)
- AO50 Current (HVAC - Coolant Temperature Too High)
- AO12 History (Low Side Temperature Sensor Circuit)
- AO15 History (Sun Load Sensor Circuit)
- AO37 History (Loss of Instrument Panel Cluster Data)
- RO61 History (SIR Indicator Circuit Failure)

What do those two letters before code-number mean? According to Chiltons and this site the codes should read EO**, But what are IO**, AO**, ja RO**?

Disconnecting the coolant temperature sensor, manifold air temperature sensor and throttel position sensor does not seem to have any effect on the stress-codes and the messages appearing on the screen - how can the car think its overheated even if the sensors are disconnected and engine has not been running for days? The fan kicks on and off randomly when the fault is active - stops when inginition turned off. I have measured the sensors and they give normal readings. The PCM should feed the coolant temperature sensor with 5V-current and it does.

Chiltons wiring diagramme is wrong, from the coolant temperature sensor and the throttle position sensor shoud come a black/pink wire to the PCM:s slot A5. The slot does have black/pink wire, but from the sensor the wire is black/light blue, and that is not connected to the A5:s black/pink wire.

Any ideas? I'm getting somewhat frustrated with this - nobody here seems to have a clue how this system works.

Is there a separate switch for fan or does it operate under the commands of the PCM?

EDIT: There is another problem with this car that also comes and goes - have not been able to if its connected to this. Cruise Control works alright sometimes, but the it can go haywire - starts to speed up and slow down by pumping the gas pedal.

EDIT2: Found the rest of the codes by help of a Finnish enthusiast:http://myweb.accessus.net/~090/dtcobd1.html#ipc

 

[dennis93coupe]

Chiltons wiring diagramme is wrong, from the coolant temperature sensor and the throttle position sensor shoud come a black/pink wire to the PCM:s slot A5. The slot does have black/pink wire, but from the sensor the wire is black/light blue, and that is not connected to the A5:s black/pink wire.

Any ideas? I'm getting somewhat frustrated with this - nobody here seems to have a clue how this system works.

EDIT2: Found the rest of the codes by help of a Finnish enthusiast:http://myweb.accessus.net/~090/dtcobd1.html#ipc

Do yourself a big favor and toss that Chiltons in the trash. Buy a FSM, (Factory Service Manual), ebay is your friend. I just looked and there are a few on there very reasonably priced. Just make sure you get the one for a Seville.

http://motors.shop.ebay.com/i.html?...&_osacat=6029&bkBtn=&_trksid=p4506.m270.l1313

 

[Arkisto]

Chiltos has not been completely useless during the years I've had this Cadillac and it even came with the car.

I do realize that its easy to come by FSM:s in the US, but to get anything bought to Finland from eBay, must;
1. The seller be willing to ship outside of the US.
2. The shipping price be known/reasonable
3. The 23% Finnish vat be paid for the price of the item and for the shipping costs.
4. I wait for 7-11 days if the seller bothers to send the item immediately.

These narrow down the supply and choices severely.. :/ But I'll try to find and buy one as recommended.

EDIT; Little over 100USD inclusive shipping costs, with VAT that would be about 125USD. Would have been in my hands in 10-14 business days. Nuts I say.

 

[dennis93coupe]

One hundred dollars? Where are you looking? Do you have a PayPal acount? I saw one on ebay for $29.99, you might try contacting the seller if he would consider shipping to Finland. Air Mail isn't all that expensive, depending on weight. (That FSM might be higher tho due to weight) I could weigh mine tonight to give you somewhat of an idea. I have shipped tools to Australia, New Zealand, UK, France, and they weren't that far out of line.

You really would throw rocks at the Chilton if you had a FSM. Chilton might be ok for basics, not for Cadillac wiring diagrams.

Read the sticky at the top of the page "How To Pull Codes". There is a better explanation of the letters before the numbers.

 

[Arkisto]

Good morning.. =)

eBay. I don't have PayPal-account - I usually buy online with just my Master. There was one that seemed to be total 43,50USD shipping included, but the seller has not replied me yet. There would of course be the vat added, but much cheaper anyhow. One answered that had checked the shipping to be nearly 55USD, but there are several ways to ship I think.

Does anyone happen to have 1992 Seville STS wiring diagrams in electric form? It would take more than two weeks to get the FSM delivered..

EDIT: tomi at arksto.com

 

[dennis93coupe]

What about alldatadiy.com. I think they have a subscription service that should work for you. It's eletronic anyway. I've never used one but have heard good things about it.

 

[Arkisto]

That seems quite promising - where might one get an discount-code? =P

Is the information there easily printable?

 

[dennis93coupe]

The nice thing about them is that they do TSB updates but I don't know that they would bother with updates on a car that old. I would think you could but not real sure. Maybe someone else can chime in on that.

Edit: Just PM'd a member that is a subscriber. You can save page as...maybe in your images or documents folder. I would also think you could print it from there. You could always ask the folks at alldatadiy.com

 

[Arkisto]

I took the 12month period for this car from www.alldatadiy.com - there seems to be a lot of information there, and everything is printable.

Found the ground-poits, and wiring diagram for PCM power and grounds too. This will keep me busy for awhile, but ideas are still welcome..

 

[dennis93coupe]

To be honest with you, get familiar with it before you try looking for a specific area. I'm not sure how they have the index laid out, the FSM has sections listed in the front and a somewhat skimpy index in the back. Going back and reading your posts with the codes tells me you should be headed in the right direction looking at grounds and circuits. Don't forget to read the TSB's, sometimes there are things that pertain to your situation. It is possible you have a bad BCM, but go through the diagnostics trouble trees to confirm what is wrong with it instead of throwing parts at it. I'm sure there isn't an abundance of parts in Helsinki for a 92 STS.

 

[ehall]

the "set timing mode" means the ECM has been put into a special operating mode, usually this is done on purpose and shouldnt ever happen on its own.

I would guess bad ECM or a bad ground.

 

[dennis93coupe]

ehall, OP had the set timing mode problem, recent poster has body codes. Maybe a moderator should start a new thread beginning from post #7.

 

[Arkisto]

This has already been worth the money: www.alldatadiy.com There is everything. Lots of fixes for faults I haven't even noticed to be faults.. Factory has even given bulletins for this car this year..

Still the ultimate problem remains unsolved..

Grounds should be checked and cleaned, but the one near started G103 is a very tight space - dunno how to get there properly. Exhaust manifold can not be removed without a severe risk of damage because of the corrosion.

This problems seems to also drain the battery, there was only about 10V left, and that wasn't enough to start the car.

A new symptom that comes and goes is the rear-door windows and central locking system. Sometimes both of the rear-door window switches do not work - the window does then work from the driver-door. At the same time central locking system only locks the doors from the rear-doors. The driver-side doors ground to the same point as the IPC, and the passenger side to the same as PCM. Both sides however operate or don't operate at the same time - it seems that at least the grounding works on these two points.

The connectors to different modules can be corroded according to one bulletin from dec 2010, and the symptoms are irregular malfunctions on different systems. These connectors should be lubricated with a dielectric grease.

TPS is original smooth-backed model that a bulletin says should be replaced - it seems to work, but I dunno - could it be the source of this?

Basically it seems that I have three different possible faults;
1. Bad PCM. Cause for it could be anywhere, or just in the PCM.
2. Bad ground/connection somewhere
3. Shortage somewhere

This can take some time.. :/

 

[dennis93coupe]

With the door switch problem you could remove the switch and use jumpers on the connectors that plug into the rocker switch that way you would know if there is a short or bad ground or bad switch. Sometimes those switches can be taken apart if you are careful.

I would definately change the TPS if it looks original and you are having problems with the TPS to ISC out of range. I have heard of people taking the ISC apart and cleaning it out, haven't tried that yet. Not sure what they have in your information, but there is a procedure that you can use to test the voltage from the TPS with a jumper harness. Don't expect to find that jumper harness, and you might be able to back probe the connector to get your readings, I have used thin paper clips to slip down between the seal and wire insulation. I made a harness from spare parts and harness end but doubt you have those resources there. I haven't heard of too many problems with PCM's but they do exist. I see STS in the salvage yard in my area frequently. It would be a crap shot but not sure if you can buy a reman PCM yet. There is also the possibility there could be a problem with the PROM in the PCM also. All of these things I hear of that fix problems with other people, I try to buy spare parts usually from a wreck as I figure it was less likely to have problems than a car that has little damage.

Yeah those billetins are real handy especially when they still issue them for cars that many years later.