wdsj Posted January 1, 2008 Report Share Posted January 1, 2008 I work on lots of old cars (to me old is pre 60's), from engine rebuilds to total car restoration. But I have never worked on "computer operated" cars. I have a 93 Sedan DeVille that recently started a strange behavior. When accelerating, ever thing is normal. When running at constant speed (any speed, just not accelerating) the speedometer swings from 0 to running speed and the transmission slips. Give it some gas and the speedometer goes normal and the tranny catches. I have not found a good description of how to interpret the 93 diagnostic system. Lots of info on newer models, but none that match what I see on this car. But when I first start the diagnostic (OFF + WARM on the CCC) I get two codes E.52 and E.75 The more I drive the car, the worse it gets. Seems to be worse on hot days. It is almost not drivable now. Any suggestions or info greatly appreciated. Link to comment Share on other sites More sharing options...
Ed Hall Posted January 1, 2008 Report Share Posted January 1, 2008 The speedometer swinging from 0 to running speed sounds like there is a problem with the speed sensor that is located on the transmission. The speed sensor is magnetic so metal filings in the transmission can work there way into the speed sensor and cause it to not work. Have you pulled the pan and changed the transmission filter? Link to comment Share on other sites More sharing options...
wdsj Posted January 1, 2008 Author Report Share Posted January 1, 2008 No, have not done anything except check the fluid level which was OK. Does a speed sensor problem relate to the transmission slipping? Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 I work on lots of old cars (to me old is pre 60's), from engine rebuilds to total car restoration. But I have never worked on "computer operated" cars. I have a 93 Sedan DeVille that recently started a strange behavior. When accelerating, ever thing is normal. When running at constant speed (any speed, just not accelerating) the speedometer swings from 0 to running speed and the transmission slips. Give it some gas and the speedometer goes normal and the tranny catches. I have not found a good description of how to interpret the 93 diagnostic system. Lots of info on newer models, but none that match what I see on this car. But when I first start the diagnostic (OFF + WARM on the CCC) I get two codes E.52 and E.75 The more I drive the car, the worse it gets. Seems to be worse on hot days. It is almost not drivable now. Any suggestions or info greatly appreciated. As Ed noted your E.75 is: P075 (E075) ................................................ Intermittent VSS Signal STOP driving it until you fix this, you need to replace the VSS, its very easy on the Northstar and I suspect it will be just as easy on your 93. I will have a look in my 91 4.9 manual, I think you have a 4.9... On the NS, there are two speed sensors the ISS and the VSS, if the ISS goes bad, the PCM uses the VSS to set pressures, etc. I don't know the specifics on your tranny, but YES, it is possible that your VSS is creating slipping and fits.... as it is potentially messing with the line pressure as its intermittant. If you keep driving it this way you could burn up your clutches.. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Ed Hall Posted January 1, 2008 Report Share Posted January 1, 2008 And I would also replace the filter and fill her back up with transmission fluid. Clutch lining material is magnetic and can find it's way into the VSS sensor. It is also quite possible you can remove the VSS sensor, clean all the junk out of it and stick her back in and it'll work fine. I had the same problem as you on my Allante and just cleaning the sensor fixed the problem. The sensor was full of junk (clutch material) from the previous owner driving the car until it would no longer would move an inch. Yes, I did have to rebuild this transmission. It cost me $80 for the rebuild kid and a weeks worth of labor. Link to comment Share on other sites More sharing options...
PAUL T Posted January 1, 2008 Report Share Posted January 1, 2008 E52 - Intermittent VSS signal This code can be caused by an open, short to ground or short to voltage in CKT400(yellow wire) &/or CKT401(purple wire); an open to shorted sensor connector, engine to dash connector, or PCM connector; or a defective VSS sensor. Locate the wiring from the sensor to the PCM and check for shorts, also check to see if they are not near any spark plug wires. Check the connectors at the sensor. Change the VSS with a known good sensor. The VSS is located on the RH rear of engine down low on the transmission housing. Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 And I would also replace the filter and fill her back up with transmission fluid. Clutch lining material is magnetic and can find it's way into the VSS sensor. It is also quite possible you can remove the VSS sensor, clean all the junk out of it and stick her back in and it'll work fine. I had the same problem as you on my Allante and just cleaning the sensor fixed the problem. The sensor was full of junk (clutch material) from the previous owner driving the car until it would no longer would move an inch. Yes, I did have to rebuild this transmission. It cost me $80 for the rebuild kid and a weeks worth of labor. This is true Ed, my ISS speed sensor looked like it had whiskers and the magnet face was obscured, I was very upset that I disturbed it without taking a photo of it to show the group. Next time Your tranny rebuild was amazing. I have rebuilt a few Turbo Hydramatic 350's and a 400 and really enjoyed doing them. I would never make money doing them however, I am slow as molasses.. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2008 Report Share Posted January 1, 2008 E52 - Intermittent VSS signal This code can be caused by an open, short to ground or short to voltage in CKT400(yellow wire) &/or CKT401(purple wire); an open to shorted sensor connector, engine to dash connector, or PCM connector; or a defective VSS sensor. Locate the wiring from the sensor to the PCM and check for shorts, also check to see if they are not near any spark plug wires. Check the connectors at the sensor. Change the VSS with a known good sensor. The VSS is located on the RH rear of engine down low on the transmission housing. Great info Paul. I always liked the expression "change the x with a known good x Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
wdsj Posted January 1, 2008 Author Report Share Posted January 1, 2008 Thanks, great info. I guess the VSS is a speed sensor that drives the speedometer? This is a little more complex than my 59 Studebaker Silver Hawk ............ Hate to sound so ignorant but, I am not used to transverse mouted engines. I assume the direction RH rear is with respect to the engine. (RH rear is drivers side, fire wall side.) What does it look like? Do you know where I could see a photo? I don't have a service manual, but looks like I need one. Is it like an oxygen sensor (size/shape), threaded into the transmission? I am up for checking the wiring, cleaning the sensor and replacing filter and fluid ! Link to comment Share on other sites More sharing options...
Ed Hall Posted January 1, 2008 Report Share Posted January 1, 2008 If your car is a 4.9, the sensor is located on the transmission on the passenger side of the car. You can see it by looking under the wheel well. It is bigger than an O2 sensor. It is aluminum and has 2 wires that go into it. Link to comment Share on other sites More sharing options...
wdsj Posted January 1, 2008 Author Report Share Posted January 1, 2008 The car has 4.9 engine does the sensor thread into the transmission or attached to it. Link to comment Share on other sites More sharing options...
Ed Hall Posted January 1, 2008 Report Share Posted January 1, 2008 I believe it has an aluminum casing that is held down to the transmission by two 10mm bolts. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 2, 2008 Report Share Posted January 2, 2008 That sounds very much like the same VSS sensor that my 1997 has. It's on the top of the half-axle. The codes show that the battery was disconnected lately and the VSS is intermittent. When the VSS drops out the TCC will release, which may seem like the transmission is slipping. If so, that's just another symptom of the VSS dropping out, not a transmission problem. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
PAUL T Posted January 2, 2008 Report Share Posted January 2, 2008 E52 - Intermittent VSS signal This code can be caused by an open, short to ground or short to voltage in CKT400(yellow wire) &/or CKT401(purple wire); an open to shorted sensor connector, engine to dash connector, or PCM connector; or a defective VSS sensor. Locate the wiring from the sensor to the PCM and check for shorts, also check to see if they are not near any spark plug wires. Check the connectors at the sensor. Change the VSS with a known good sensor. The VSS is located on the RH rear of engine down low on the transmission housing. Great info Paul. I always liked the expression "change the x with a known good x Yea, I got that out of the manual. Its says it like you might have an extra one lying around and that if that is not causing the problem you will change it back. I guess the manuals were made for the GM mechanics that may have extra parts lying around. Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 2, 2008 Report Share Posted January 2, 2008 E52 - Intermittent VSS signal This code can be caused by an open, short to ground or short to voltage in CKT400(yellow wire) &/or CKT401(purple wire); an open to shorted sensor connector, engine to dash connector, or PCM connector; or a defective VSS sensor. Locate the wiring from the sensor to the PCM and check for shorts, also check to see if they are not near any spark plug wires. Check the connectors at the sensor. Change the VSS with a known good sensor. The VSS is located on the RH rear of engine down low on the transmission housing. Great info Paul. I always liked the expression "change the x with a known good x Yea, I got that out of the manual. Its says it like you might have an extra one lying around and that if that is not causing the problem you will change it back. I guess the manuals were made for the GM mechanics that may have extra parts lying around. I actually took that approach recently diagnosing my x's Monte Carlo, I bought a new coil and swapped it in.., fixed the problem. They have been making that statement for years... I like it Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
wdsj Posted January 12, 2008 Author Report Share Posted January 12, 2008 I purchased a shop manual. Found it, cleaned it, fixed it! the sensor was coated with very fine metal thanks Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 12, 2008 Report Share Posted January 12, 2008 I purchased a shop manual. Found it, cleaned it, fixed it! the sensor was coated with very fine metal thanks NICE JOB, thanks for reporting back your experience.... Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
wdsj Posted September 6, 2009 Author Report Share Posted September 6, 2009 Just to close this out for me, cleaning the sensor did not fix the problem. After much wiring checks, I found a leak in two wires connected to the sensor. Not a short, but not an open circuit either. I seperated the wires (two wire bundle) and measured an open circuit. There was no evidence of wire damage to the eye. Coated the wires with liquid tape and problem has not returned. This was a tricky one, the leak was very small but when you should have an open circuit, you have an open circuit (infinite resistance) Hope this helps someone. Link to comment Share on other sites More sharing options...
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