Error code E31 (93 Deville 4.9L)
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 9 of 9
HT4100 4.1, 4.5, 4.9 Discussion, Error code E31 (93 Deville 4.9L) in Cadillac Engine Technical Discussion; I just pulled the codes for my new Caddy and i'm getting F48 (no biggie i'll put in some refrigerant, ...
  1. #1
    jfolker is offline Cadillac Owners Member
    Join Date
    Mar 2004
    Posts
    34

    Error code E31 (93 Deville 4.9L)

    I just pulled the codes for my new Caddy and i'm getting F48 (no biggie i'll put in some refrigerant, i have the tools) and a E31. I know it's the MAP sensor, can anyone tell me where it's located and how to diagnose this further?

    Thanks,
    JF

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    50
    Posts
    9,577

    Re: Error code E31 (93 Deville 4.9L)

    I think the MAP sensor is mounted off the backside of the throttle body...actually it is the front side of the throttle body....towards the front of the engine or the right side of the car. Follow the vacuum hose off the throttle body to the small, rectangular box like device with a vacuum hose going to it and a wiring connector attached. Check for disconnected lines, wires, holes in the vacuum hose, etc..... If all else is OK then likely replacing the MAP sensor is required. Simple and quick. Nothing to set or adjust. Just R&R the MAP sensor.

  4. #3
    jfolker is offline Cadillac Owners Member
    Join Date
    Mar 2004
    Posts
    34

    Re: Error code E31 (93 Deville 4.9L)

    Cool, thx for the help. Is there a negative side effect to not replacing it? Probably poor gas mileage and performance...

  5. #4
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
    Join Date
    Dec 2002
    Location
    Fort Lauderdale, Florida
    Age
    50
    Posts
    9,577

    Re: Error code E31 (93 Deville 4.9L)

    Quote Originally Posted by jfolker
    Cool, thx for the help. Is there a negative side effect to not replacing it? Probably poor gas mileage and performance...
    Since the MAP sensor provides the only input to the PCM to calculate the fueling and spark delivery I would say that it is important to the system....yes.... Without the MAP sensor the engine control is very very compromised.

    In most speed density fuel injection systems the engine would not even run without the MAP sensor. Period. You are experiencing one of the benefits of the onboard diagnostic system....the system has detected a failed sensor (a vital one at that) and has warned you with the light and has implemented a backup mode of operation using certain "fail soft" values in the fuel and spark calculation that are designed to keep the engine running despite the loss of vital information until a repair is made. The failsoft values are carefully selected to provide safe operation that will not harm the emission control devices although the emission performance, driveability and fuel economy will be compromised until the repair is made. The fail soft logics and values provide and electronic redundancy in the system to prevent walkhome failures.

    Get the MAP fixed.

  6. #5
    jfolker is offline Cadillac Owners Member
    Join Date
    Mar 2004
    Posts
    34

    Re: Error code E31 (93 Deville 4.9L)

    Point taken.

  7. #6
    up2ng's Avatar
    up2ng is offline Cadillac Owners Member
    Join Date
    Dec 2003
    Location
    New York
    Posts
    87

    Just in case

    That sensor is in the middle of the rear valve cover, right behind the EGR valve and under the bar that goes between strut towers. It's on it's own pedestal about 4 inches above the motor.

  8. #7
    jfolker is offline Cadillac Owners Member
    Join Date
    Mar 2004
    Posts
    34

    Re: Error code E31 (93 Deville 4.9L)

    Replaced and the code went away, now for the SERVICE SSS light and the ABS light. Just replaced front hub assemblies.

  9. #8
    90devilleguy's Avatar
    90devilleguy is offline Cadillac Owners Enthusiast
    Automobile(s): 2002 SLS & 1962 Coupe Deville
    Join Date
    Nov 2003
    Location
    Framingham,Ma
    Posts
    535

    Re: Error code E31 (93 Deville 4.9L)

    Quote Originally Posted by jfolker
    Replaced and the code went away, now for the SERVICE SSS light and the ABS light. Just replaced front hub assemblies.
    was your engine stumbling to accelarate?like it was jumping around up and down

  10. #9
    jfolker is offline Cadillac Owners Member
    Join Date
    Mar 2004
    Posts
    34

    Re: Error code E31 (93 Deville 4.9L)

    Not really, the engine seemed to run ok, a bit rich, but now i have an e13 because my o2 sensor is faulty. It gets like 13.5 avg mpg.

    If your car is doing that, I wouldn't rule it out, bad MAF and MAP sensors (MAF=Mass Air Flow, MAP=Manifold Absolute Pressure; Different cars use diff. methods) will cause a stumble in the car.

    THanks,
    jf

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

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

Please enter a valid email address for yourself.

Log-in

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.



Bookmarks

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