SERVICE SOON telltale light!!

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 5 of 5
HT4100 4.1, 4.5, 4.9 Discussion, SERVICE SOON telltale light!! in Cadillac Engine Discussion; Hi I am directing this too the HT4100 experts. My 86 CDV running very nicely but on occasion my Service ...
  1. #1
    tallpat's Avatar
    tallpat is offline Cadillac Owners Fanatic
    Automobile(s): 1986 Coupe Deville
    Join Date
    Oct 2006
    Columbia, Maryland, United Sta

    Smile SERVICE SOON telltale light!!

    Hi I am directing this too the HT4100 experts. My 86 CDV running very nicely but on occasion my Service soon telltale light comes on and stays on.
    when I shut off the car and restart its gone I haven't pull the codes yet. I thought I read that these lights are nortorious for going off for no reason.
    Or maybe I have an O2 sensor going bad. any ideas I will post any codes I get ASAP.


  2. Remove Advertisements

  3. #2
    awadecki is offline Cadillac Owners Enthusiast
    Automobile(s): 76 Eldo (54k), 76 Eldo (52k), 78 Eldo (9k), 85 Deville (43k)
    Join Date
    Jun 2005

    Re: SERVICE SOON telltale light!!

    Check your codes by pressing and holding "off" and "warmer," that should tell you what the issue is. Watch the Fuel Data Center for the codes and check the OBD I listing at the top of the forum page.

  4. #3
    noahsdad's Avatar
    noahsdad is offline Cadillac Owners Connoisseur
    Automobile(s): '87 SDV
    Join Date
    Jun 2005

    Re: SERVICE SOON telltale light!!

    Agreed. The SES light is almost always set by an issue that produces a trouble code. Since the car is running okay and the light is intermittent, my money is on a TPS adjustment or an EGR problem.

  5. #4
    86cadman is offline Cadillac Owners Member
    Automobile(s): 1986 Cadillac Sedan DeVille, 1998 Cadillac Sedan DeVille
    Join Date
    Oct 2006

    Re: SERVICE SOON telltale light!!

    Probably just a TPS error, mine did it all the time usually when I put the gas down and held it there, try letting up immediently and going lite on the gas when it comes on, or tap the pedal a few times, that worked to make mine go off, not really a problem, just a nuisance though.

  6. #5
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003

    Re: SERVICE SOON telltale light!!

    These are at best, guesses. Perform the on board diagnostics and post the codes found. The service eng light always means something is working incorrectly or not at all. Upon restart, the ECM will wait to retest the faulty system and if still faulty, will turn on the light again.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

What Cadillac(s) do you own? (Or type NONE)

Please select your insurance company (Optional)

Your date of birth and age are displayed in several places on the forum. Only the administrator will have access to your date of birth should you choose to hide it via the privacy option below.


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting