Adonaischild Posted June 25, 2007 Report Share Posted June 25, 2007 Okay, tonight I was driving home from church and I thought I saw the digital temperature reading say -96 so I watched it closer and the next time it came around it read 160. But, every once in a while it looked like it was reading a negative number so I just kept the information panel on engine temperature and sure enough negative numbers were popping up. One minute it was a negative number, then no numbers, then normal numbers. Any ideas? My son ran the battery down a few weeks ago, but we reset the computer the way the manual tells us to (parking brake set, let idle 20 minutes--climate control on auto, let idle 2-3 minutes--put in drive and idle 2-3 minutes) so I don't think that is it. The only thing new we did was finally put in a new EGR valve and replaced a broken spark plug. My husband checked all the fluids and they are great. Of course, he isn't home right now to take to car for a drive and see the crazy temps it's reading. No codes are coming up but the service engine soon light came on. Oh yeah, my Caddy is a 1992 Seville. Thanks for any help! April Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 25, 2007 Report Share Posted June 25, 2007 It sounds like you have a bad coolant temperature sensor or a loose connector. Check for computer codes and post them here, you probably have a temp sensor code in history, if the service engine light came on.. 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...
Ranger Posted June 25, 2007 Report Share Posted June 25, 2007 Are you talking about engine temperature or outside air temperature? Link to comment Share on other sites More sharing options...
adallak Posted June 25, 2007 Report Share Posted June 25, 2007 SES without a code? Strange. Sounds like an electrical problem (bad ground?) The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Adonaischild Posted June 25, 2007 Author Report Share Posted June 25, 2007 I looked up the history codes and have a EO 15 (Open Coolant Temp Sensor Signal) and an EO 73 (Intermittent Coolant Sensor Signal). So, what does this mean? What are history codes anyway? I never paid attention to them because I thought they were things that were wrong with the car at one time but no longer needed fixing. If they are codes of things that still need fixing then what does EO 30 (ISC RPM out of range) mean? Thanks for your Caddy wisdom! April Link to comment Share on other sites More sharing options...
JimD Posted June 25, 2007 Report Share Posted June 25, 2007 I looked up the history codes and have a EO 15 (Open Coolant Temp Sensor Signal) and an EO 73 (Intermittent Coolant Sensor Signal). So, what does this mean? It could mean the wires and/or connector that attach to the sensor are loose, corroded, or damaged. Or it could mean the coolant temperature sensor is failing. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Patrick7997 Posted June 25, 2007 Report Share Posted June 25, 2007 The outside temperature sensor in my Corvette died, and it behaved exactly like yours. Crazy numbers all over the map, with no relation to the actual outside temperature... Which obviously drove the climate control system crazy... Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 25, 2007 Report Share Posted June 25, 2007 I looked up the history codes and have a EO 15 (Open Coolant Temp Sensor Signal) and an EO 73 (Intermittent Coolant Sensor Signal). So, what does this mean? What are history codes anyway? I never paid attention to them because I thought they were things that were wrong with the car at one time but no longer needed fixing. If they are codes of things that still need fixing then what does EO 30 (ISC RPM out of range) mean? Thanks for your Caddy wisdom! April As I noted earlier along with Jim, its either a bad connection to your coolant temp sensor or a bad sensor. Someone post the location of the temperature sensor on the 4.9 for April, I am at work and my manual is at home.. A HISTORY code is a problem that happened, but it is not CURRENT. An intermittant problem like you have, creates HISTORY codes if you have a bad connection or a sensor that is beginning to go and is good and bad...or intermittant. When the connection goes OFF briefly it sets a code but if it reconnects that code is NOT CURRENT, it becomes HISTORY. That is why I said above you might find your problem in HISTORY (since you said you had no codes)... 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...
adallak Posted June 25, 2007 Report Share Posted June 25, 2007 I looked up the history codes and have a EO 15 (Open Coolant Temp Sensor Signal) and an EO 73 (Intermittent Coolant Sensor Signal). So, what does this mean? What are history codes anyway? I never paid attention to them because I thought they were things that were wrong with the car at one time but no longer needed fixing. If they are codes of things that still need fixing then what does EO 30 (ISC RPM out of range) mean? Thanks for your Caddy wisdom! April As I noted earlier along with Jim, its either a bad connection to your coolant temp sensor or a bad sensor. Someone post the location of the temperature sensor on the 4.9 for April, I am at work and my manual is at home.. I am at work too, but am pretty sure it is close to the thermostat. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 25, 2007 Report Share Posted June 25, 2007 I looked up the history codes and have a EO 15 (Open Coolant Temp Sensor Signal) and an EO 73 (Intermittent Coolant Sensor Signal). So, what does this mean? What are history codes anyway? I never paid attention to them because I thought they were things that were wrong with the car at one time but no longer needed fixing. If they are codes of things that still need fixing then what does EO 30 (ISC RPM out of range) mean? Thanks for your Caddy wisdom! April As I noted earlier along with Jim, its either a bad connection to your coolant temp sensor or a bad sensor. Someone post the location of the temperature sensor on the 4.9 for April, I am at work and my manual is at home.. I am at work too, but am pretty sure it is close to the thermostat. I believe you are correct 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...
thu Posted June 27, 2007 Report Share Posted June 27, 2007 I've got my 1992/1992 Deville FSM handy here. Your Seville may be a bit different. Regarding E15, Open coolant temperature sensor signal. Here are some excerpts: The coolant sensor is a thermistor, a sensor whose resistance varies with temperature. The coolant sensor signal is on CKT 410 and the sensor ground on CKT 476. As the temperature of the sensor increases, the resistance decreases. HIgh coolant temperature will result in low signal voltage on CKT 410. Code E15 'Open Coolant Sensor" sets because coolant temperature cannot be less than -38*C when Manifold Air Temp (MAT) is greater than -5*C. Notes on Intermittents: Manipulate coolant sensor wiring, coolant sensor connector, and PCM connectyor while observing PCM Data P.0.4. If the coolant temperature jumps from a normal reading to -38*C or less, repair the intermittent open circuit on CKT 410 or 476. Remove and reconnect both the coolant and PCM connectors and retest before replacing any components. If wiring and connectors check out OK, substitute a known good coolant sensor and retest. On the 4.9L, the CTS (Coolant Temp Sensor) is located to the right of and next to the distributor. There's a connector right on it. The CTS mounts right in the block, into the coolant cavity. From the pics, it looks like it's not too far, but forward from the thermostat. 2003 Seville STS 43k miles with the Bose Sound, Navigation System, HID Headlamps, and MagneRide 1993 DeVille. Looks great inside and out! 298k miles! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.