SES Light '90 Eldorado

[RichieR]

Hello,

I need the following advice pertaining to the Service Engine Soon light coming on and erratic operation on a '90 Eldorado with the 4.5L SPFI engine. This problem occurs intermittently. The only trouble code that displays is E049 which is "A.I.R. Control Problem". When the SES light is on and the code is current, the car will become sluggish and it will stall, but it will start up immediately. Sometimes, the car will even stall at highway speeds, but it will always restart right away. When the SES light is not on, the car runs perfectly. I would say this occurs every 5 or so starts with the same symptoms. What is the potential fix for this problem.

Also, I have a book with Cadillac trouble codes for each year and I noticed that code E049 (A.I.R. control problem) is only listed for the '90 Cadillacs - this is the only year that the 4.5 liter had SPFI. The '88 & '89 Cadillacs had the 4.5L with Throttle Body FI - this code is not listed for those years, and the '91 had the 4.9 Liter and again, this code was not listed in the list of trouble codes for '91 and later. Why wouldn't there be a trouble code for the A.I.R. system in other years besides '90.

Any advice would be appreciated.

[Bruce Nunnally]

the AIR is an Air Injection system which was a type of emission control that added additional air to the exhaust flow

http://www.carcare.org/Emission_Control/air_injection.shtml

So perhaps the air pump is inoperative, or the valve needs replacement?