QuestionJust went out to start the 90'coupe DeVille with a 4.5L engine and I heard a thumping sound when I turned the ignition to on. The engine started OK, but the "service engine soon" light came on with trouble codes 22 and 38 (open TPS circuit and open MAT sensor circuit). The car was running fine the last time I used it one week ago.
What could have caused this to happen all of a sudden?
Can the cold temperature cause these sensors to malfunction?
Are they entirely electrical in operation or are there mechanical or vacuum components?
Should I replace either one or both or see if the connections might not be good?
How easy or difficult is it to get to these components to check them or replace them?
How expensive are the components?
Any advice would be greatly appreciated
Answer1. A 17 year old wiring circuit or 17 year old device, dirty engine.
2. The cold weather would create condensation that gets into the device and then turns into water and sends the sensor out the door.
3. There are vacuum components.
4. First use a test light and make sure they are getting power, and then replace them.
5 & 6. The hardest part about replacing these is the wallet part.
7. A haynes book will be very helpful in replacing this.
