E48 - EGR System Problem 91 cadillac deville - 1992 Cadillac DeVille

SOURCE: No heat in 91 Cadillac Sedan Deville

I would beleive more that you have build up in the heater core. Try taking loose the heater hoses from the block and use a water hose to spray into one of the hoses letting it come out the other hose then switch hoses with the water hose and keep reverseing for 2/3 times each hose. sounds like stop leak may have been used in a prior time and may be blocking water flow.

Good luck,
Lugnut61

SOURCE: 1998 cadillac deville

try taking off your fuse panel cover, there should be a reset button in there.

SOURCE: 2001 cadillac deville, overheats without loss of coolant

First, provided their are no visible coolant leaks and/or loss of coolant with no signs of leaks, I would thoroughly flush cooling system and replace coolant, then check and/or replace thermostat (you can place thermostat in boiling water to check for proper function), if you have tried these 2 steps and still are experiencing overheating you may need to replace your water pump which can be a tricky job if you're unfamiliar and try to do it yourself, however, I could walk you through it if necessary. Also visually check your radiator hoses for bulges, wear ,etc along with heater hoses etc. You may want to also check radiator fins to see if they are dirty/obstructed and clean if necessary. Let me know if I can assist you further and how it works out

SOURCE: 93 Cadillac 3 codes E48 E75 and E98 How to fix?

timing should help the idle issue. and the vss probly needs to be replaced.check the egr diaphram its gold and is underneeth the air breather. push up on the bottom of diamphram it should move without alot of efort. if not replace it

SOURCE: prndl switch problem error code e91 and ee 91.92 cadillac deville

the switch on top of the transmission where the shift cable is . it probly is not anny good. check all wiring . make sure thair is no dirt inside the connector