Cadillac Check Engine Light Stays On

Is your Cadillac Check Engine Light ON or Flashing? In this guide, you will learn about common problems that trigger Cadillac check engine light to come on.

You will also find step-by-step instructions on how to diagnose the Cadillac check engine light yourself.

Symptoms

Symptoms of a check engine light can vary depending on the fault code that triggered the light. Possible symptoms include:

Poor throttle response
A decrease in fuel economy
Engine misfire
Difficult to accelerate or going uphill
Engine shakes or excessive vibrations
Car won't stay running

The check engine light may be on, with no symptoms. Even if there are no symptoms it is important to read the fault codes to find out why CEL is on.

Common Causes

Cadillac check engine light can turn on for various reasons including something as simple as a loose gas cap.

Loose gas cap
Faulty MAF sensor
Oxygen sensor
Catalytic converter
EVAP leak
Vacuum leak
EGR Valve

It is difficult to know the cause of the check engine light without reading the codes.

How to read Cadillac codes

The following steps provide information on how to read Cadillac fault codes from the Engine Control Unit (ECU).

What you will need

OBD-II scanner

You can purchase a scanner online or borrow one from your local auto parts store.

Procedure

Locate the OBD-2 port under the dashboard of your Cadillac on the driver's side. This is a 16-pin port and all 1996 and newer Cadillac vehicles have this port.
Connect Scanner. Plugin your scanner or Bluetooth adapter into the OBD2 port.
Turn ignition ON, key in position II. All Cadillac dashboard lights will turn on but do not start the engine. If your Cadillac has Start/Stop button you will need to press the START button without pressing the brakes.
Turn on the scanner. Allow your OBD2 scanner to turn on and connect to your Cadillac Engine Control Unit (ECU). This step can take up to one minute.
Read Codes. Read Cadillac check engine light codes from the Engine Control Unit (ECU)
Clear Codes. Once you have read the codes and fixed the underlying problem, you can come back to clear Cadillac CEL codes. Go to the Erase Codes menu. Select YES to clear the Cadillac check engine light.
Check engine light codes should only be cleared (erased) only after the problem that triggered the light has been fixed.

Reading Cadillac check engine light codes and resetting it once you fix the problem is very easy. Any Cadillac owner can read and clear the Cadillac check engine light at home.

This procedure works on Cadillac ATS, CTS, XTS, CT6, XT5, Escalade, SRX, DTS, STS, BLS, XLR, and other models.

OnStar Subscribers

If you are subscribed to OnStar, press the button to connect to an Advisor. They can run a diagnostic check and retrieve the trouble code(s) from the Engine Control Unit (ECU).

If you are not subscribed to OnStar follow the instructions to read the fault codes yourself. This procedure is very easy and takes less than five minutes.

Cadillac

Visitor

Member since 2020-07

I have a 2007 escalade and I have few warning lights on. The scanner pointed me to a couple of the problems but on a couple others it said it cant connect to the ecu. Why is it reading some problems and not others?

Visitor

Member since 2020-07

Can a past due on you're oil change or due on the date cause check engine light to come on a ats 2014

Visitor

Member since 2020-07

No the check engine light should not come on because you haven't changed the oil. Hope this helps.

Visitor

Member since 2020-07

My car has less then 96k miles and the check engine light came on and it showed codes p0017 & p0008. Gm issues a service bullentin (11340) and later extended it to include the 2009 Cts ( 11340c) for premature timing chain wear. Even though my cars make, model and year is listed under sb 11340c, when you call gm, they say my VIN isn't included. Obviously, my car which year is listed should be covered and gm should repair under this sb. It is the exact same issue the sb was issued for. Gm is scamming their customers and there needs to be a recall for this issue. I read thousands of people complaining about the same issue, and all that needs to happen is for the htsa to require all the 2009 Cts that had to have this issues repaired at their own expense while gm reaps the rewards of each car that they have a known engineering issue.