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94 seville help asap trying to keep her from the scrap yard


angealus

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Hi I have a 94 seville sts with the northstar engine, I love this car and really want to keep it after all the money and time I invested. My dashboard used to start fine and every once and a while the outside temp on the climate control would read -- and that would follow by the left side instrument and inside temp follows showing the same thing -- , --, -- as well as this the defogers get stuck on. this would happen for twenty or so minutes and then the dashboard instruments would come back to normal and I could turn off the defogers this problem is becoming more of a constant ocurrence with less of the dash and defoggers working properly. when I check the dash for codes I am seeing

I032

I033

I034

I037

I039

Please any help would be greatly appreciated and I am a beginner so as much detail and explanation would be greatly appreciated..

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Too many codes. The chances are you have bad electrical connections at the battery and the grounds. Also disconnect-reconnect at least TEN times PCM and AC programmer to recondition the connections (clean corrosion).

The saddest thing in life is wasted talent

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Could be a bad IPC. It's displaying all the classic signs of a bad IPC. Fuel and Hvac displays go '--' blank...defrost kicks in...warning messages...codes are:

IO32 'loss of abs data'

IO33 'loss of sir data'

IO34 'loss of pcm data'

IO37 'loss of acp data'

IO39 'loss of rss data'

All the computers 'talk' to each other on circuit 800. If one of the system computers goes bad, it can mess up the data on circuit 800.

A scan tool really does no good on this problem.

Using a DVOM, you can measure the voltage of circuit 800 at pin M on the ALDL. Voltage should be 3-5v and fluctuating all the time. If the voltage locks up, about 15-20 seconds latter you'll see the classic '--' blank display and warning messages.

The problem can be any one of the computers on the loop. You unplug each computer one at a time to find the bad one.

That said, many times. It is the IPC causing the problem. It is a known, common, IPC problem.

You can get reman IPC units at Delco radio/speeometer repair shops. One problem, in their test mode, '--' is a normal display. The Delco equipment is not designed to see this failure mode. It sometimes takes 2-3 reman IPC units to find a good one.

I attatched a pic of a GM ALDL. That era of Cadillac should have a cover on the ALDL. Inside the cover will be a jumper to complete the circuit 800 loop when plugged in.

This can be a very difficult problem to pin point. My '93 was a 'once every 500 miles' one..

post-2-128550669681_thumb.gif

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Could be a bad IPC. It's displaying all the classic signs of a bad IPC. Fuel and Hvac displays go '--' blank...defrost kicks in...warning messages...codes are:

IO32 'loss of abs data'

IO33 'loss of sir data'

IO34 'loss of pcm data'

IO37 'loss of acp data'

IO39 'loss of rss data'

All the computers 'talk' to each other on circuit 800. If one of the system computers goes bad, it can mess up the data on circuit 800.

A scan tool really does no good on this problem.

Using a DVOM, you can measure the voltage of circuit 800 at pin M on the ALDL. Voltage should be 3-5v and fluctuating all the time. If the voltage locks up, about 15-20 seconds latter you'll see the classic '--' blank display and warning messages.

The problem can be any one of the computers on the loop. You unplug each computer one at a time to find the bad one.

That said, many times. It is the IPC causing the problem. It is a known, common, IPC problem.

You can get reman IPC units at Delco radio/speeometer repair shops. One problem, in their test mode, '--' is a normal display. The Delco equipment is not designed to see this failure mode. It sometimes takes 2-3 reman IPC units to find a good one.

I attatched a pic of a GM ALDL. That era of Cadillac should have a cover on the ALDL. Inside the cover will be a jumper to complete the circuit 800 loop when plugged in.

This can be a very difficult problem to pin point. My '93 was a 'once every 500 miles' one..

I have a multimeter and will check using the method you described can anybody please tell me how many computers the 94 seville has, names, locations etc thanks as i said before i am learning and really appreciate it, and I will look for bad body grounds under the hood. I think there is a computer under the hood I will start following wires.. Thank you for all the help so far

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Too many codes. The chances are you have bad electrical connections at the battery and the grounds. Also disconnect-reconnect at least TEN times PCM and AC programmer to recondition the connections (clean corrosion).

do you know where the pcm and ac programmer are thank you, and i will start googling to find out.

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Too many codes. The chances are you have bad electrical connections at the battery and the grounds. Also disconnect-reconnect at least TEN times PCM and AC programmer to recondition the connections (clean corrosion).

do you know where the pcm and ac programmer are thank you, and i will start googling to find out.

I do not. Someone with 94 STS will chime in, I am sure. If you want to take care of your Cadillac yourself, I would recommend buying a Factory Service Manual (FSM)on eBay. If you watch eBay, you will get a better deal.

The saddest thing in life is wasted talent

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I really do like the second generation STS like yours! I had a 93 myself a couple of years ago and still have the FSM.

It's not up for sale because I do want to help someone occasionally ;)

Listen to Logan especially, he is the data and electrical guru around here!

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The PCM is located beneath the right portion of your instrument panel right behind and to the right of the knee bolster on the passenger side.

The AC programmer is located behind the PCM. I don't know if it is possible to reach the electrical connectors without removing the glove compartment but if you do just chime in.

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The PCM is located beneath the right portion of your instrument panel right behind and to the right of the knee bolster on the passenger side.

The AC programmer is located behind the PCM. I don't know if it is possible to reach the electrical connectors without removing the glove compartment but if you do just chime in.

i have removed the glove compartment already and i have found the following wires to the right of the engine that have been partially chewed threw corroded and stuck together i am tracing them now to see where they stop and start. the location is right next to the transmission cap going into throttle body and the other side goes to the side of the engine and disappears I have a pic for anybody who is interested just leae your email its to big for the server

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

i removed both plugs from the top going into the ipc and the defogers still remained on. I will check the plugs in the pcm (which i believe is the main computer in the dash on the passenger side. I am having problems locating the ac programmer.. thnks for the responses and patience peoples as i said i am very new

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

i removed both plugs from the top going into the ipc and the defogers still remained on. I will check the plugs in the pcm (which i believe is the main computer in the dash on the passenger side. I am having problems locating the ac programmer.. thnks for the responses and patience peoples as i said i am very new

does anybody know where the bcm is on a 94 caddi sts seville

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

i removed both plugs from the top going into the ipc and the defogers still remained on. I will check the plugs in the pcm (which i believe is the main computer in the dash on the passenger side. I am having problems locating the ac programmer.. thnks for the responses and patience peoples as i said i am very new

does anybody know where the bcm is on a 94 caddi sts seville

Most likely next to PCM and the programmer.

The saddest thing in life is wasted talent

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

i removed both plugs from the top going into the ipc and the defogers still remained on. I will check the plugs in the pcm (which i believe is the main computer in the dash on the passenger side. I am having problems locating the ac programmer.. thnks for the responses and patience peoples as i said i am very new

does anybody know where the bcm is on a 94 caddi sts seville

Most likely next to PCM and the programmer.

okay peoples I appreciate the help and I have gotten a multi meter to test continuity. I unplugged the top right main plug that goes into the climate control side on the top of the ipc which is a blue plug and unplugged the blue plug on the pcm that is located on the passenger side under the kicker guard and i get continuity on a few of the pins on the ipc side. I guess my question is, are all the wires that go from the ipc plugs shoot directly to the pcm or do they branch off into other systems and is that why I am not getting continuity onn all pins???? the computer I am talking about has three different plugs going into it red, blue, and white and have a prom module so you guys know in case I am not giving you the right names. logan I think you were right about data lines....

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Could be a bad IPC. It's displaying all the classic signs of a bad IPC. Fuel and Hvac displays go '--' blank...defrost kicks in...warning messages...codes are:

IO32 'loss of abs data'

IO33 'loss of sir data'

IO34 'loss of pcm data'

IO37 'loss of acp data'

IO39 'loss of rss data'

All the computers 'talk' to each other on circuit 800. If one of the system computers goes bad, it can mess up the data on circuit 800.

A scan tool really does no good on this problem.

Using a DVOM, you can measure the voltage of circuit 800 at pin M on the ALDL. Voltage should be 3-5v and fluctuating all the time. If the voltage locks up, about 15-20 seconds latter you'll see the classic '--' blank display and warning messages.

The problem can be any one of the computers on the loop. You unplug each computer one at a time to find the bad one.

That said, many times. It is the IPC causing the problem. It is a known, common, IPC problem.

You can get reman IPC units at Delco radio/speeometer repair shops. One problem, in their test mode, '--' is a normal display. The Delco equipment is not designed to see this failure mode. It sometimes takes 2-3 reman IPC units to find a good one.

I attatched a pic of a GM ALDL. That era of Cadillac should have a cover on the ALDL. Inside the cover will be a jumper to complete the circuit 800 loop when plugged in.

This can be a very difficult problem to pin point. My '93 was a 'once every 500 miles' one..

please review my latest post and let me know what you think

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First things first!

Did you perform the test as per Logans instructions?

Just some general info. It is important that you have the ignition OFF when disconnecting the main connectors, otherwise components can be toasted!

Ok, the connector on the IPC is numbered C1, the one on the PCM is numbered C205.

From what I gather the connectors in question are white on both the IPC and the PCM.

On the C1 pin C2 is the one for the IPC/PCM connection.

On C205 the pin K is for the IPC/PCM connection.

The wire is tanned.

Between the PCM and the HVAC the wire starting at C205 connector pin G and ending with C11 on the HVAC is in question.

Also tanned

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Ok, good catch on finding the wires, but they are not related to your problem.

It seems like you found the cable harness running to the injectors.

Either the IPC is bad or something is wrong with the communication line, just as Logan said.

It won't hurt to check the PCM and AC programmer connections as mentioned earlier. Be sure you don't have the ignition on and pull the contacts and spray them down with WD-40 and check for kinks on the wires and contact pins being bent or dislocated.

i removed both plugs from the top going into the ipc and the defogers still remained on. I will check the plugs in the pcm (which i believe is the main computer in the dash on the passenger side. I am having problems locating the ac programmer.. thnks for the responses and patience peoples as i said i am very new

hi guyz just an update on diagnosing the problem, Logan hope you are listening. I have put my multimeter into pin m with all the computers plugged in and my meter reads 0.000, now as soon as I unplug the hvac the meter jumps to 4.whatever so I believe I have found the problem which has to do with the hvac computer thank you for all the help and tips the only thing left for me to do is hit the scrap yard again thank you guys... and any responses confimring my conclusions would be greatly appreciated....

does anybody know where the bcm is on a 94 caddi sts seville

Most likely next to PCM and the programmer.

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hi guyz just an update on diagnosing the problem, Logan hope you are listening. I have put my multimeter into pin m with all the computers plugged in and my meter reads 0.000, now as soon as I unplug the hvac the meter jumps to 4.whatever so I believe I have found the problem which has to do with the hvac computer thank you for all the help and tips the only thing left for me to do is hit the scrap yard again thank you guys... and any responses confimring my conclusions would be greatly appreciated....

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  • 2 weeks later...

Got three ipc's from the scrap yard put one in and have been driving the car for three days with no problems thank you very much everybody. They don't sell new ones anymore you have to send them away to get reconditioned and it's 70 - 90 for them just to look at it

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Got three ipc's from the scrap yard put one in and have been driving the car for three days with no problems thank you very much everybody. They don't sell new ones anymore you have to send them away to get reconditioned and it's 70 - 90 for them just to look at it

Glad you solved the problem.

Logan is as usual solid as a rock!

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Got three ipc's from the scrap yard put one in and have been driving the car for three days with no problems thank you very much everybody. They don't sell new ones anymore you have to send them away to get reconditioned and it's 70 - 90 for them just to look at it

Glad you solved the problem.

Logan is as usual solid as a rock!

yeah logans the shi#

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