Is the Check Engine Light appearing on your Buick? Learn the cause of why it is illuminating and know possible solutions on how to fix the problem using an OBD-II Scanner.

The Buick check engine light comes on when a problem is detected by the On-Board Diagnostic (OBD) system with the engine, transmission, or Evaporative Emission Control (EVAP). Buick check engine light may be called CEL, Malfunction Indication Lamp, MIL, Service Engine Soon, or SES light.

2002 Buick Lesabre Check Engine Light

Check engine light may come on due to something as simple as a loose or defective gas cap. It can also indicate a more serious engine problem, transmission issue, or EVAP leak.

Buick\Lacrose\2013 check engine light

The check engine light does not provide much information on what is wrong with the vehicle. This guide will teach you how to read the fault codes yourself using an OBD-II scanner.


Common symptoms you may notice:

  • The engine runs rough or won’t stay running.
  • Check engine light is always on or flashing.
  • Engine overheating
  • Lack of power
  • Poor throttle response
  • Engine noise
  • Smoke from the exhaust
  • The vehicle won’t shift gears; stuck in limp mode.

You may not notice any performance symptoms if your Buick check engine light is on due to an EVAP leak.

Common problems that trigger Buick check engine light to come on?

buick check engien service engine light on

Common problems that trigger Buick check engine light to come on include worn spark plugs, bad oxygen sensor, faulty MAF sensor, defective Ignition coil, clogged catalytic converter, or loose gas cap.

Buick check engine light triggered by maf sensor

Hundreds of possible issues can trigger the Buick check engine light to come on. To find out why your Buick to check engine light is on, read the fault codes with an OBD-II scanner.

  • MAF Sensor – Mass airflow (MAF) sensors can become clogged with dirt over time, especially if performance filters are used. A dirty MAF sensor will give false readings, resulting in incorrect air-fuel mixture and engine running issues. Occasionally, dirt buildups can be easily cleaned with a MAF cleaner fluid. Another possibility is a loose connector. Related Code: P0102
  • Various vacuum leaks can cause engine running issues, especially at idle or low engine speeds. Tracking leaks can sometimes be difficult, and you may need a smoke-generating machine. Related Code: P0171 – system too lean
  • Catalytic Converter – Any higher-mileage Buick will likely have emission control issues triggering a check engine light. In most cases, it is either caused by a clogged catalytic converter or a faulty downstream O2 sensor. Related Codes: P0410 and P0420
  • Variable Valve Timing Issue – Problems with Variable Valve Timings are quite common on a 3.6L V6 engine. Furthermore, to check the engine light, you will notice a lack of acceleration, stalling, and poor throttle response. The problem is usually within the timing chain, which needs to be replaced as soon as possible. Related Code: P0008
  • EGR Valve – the EGR-related problem is, in most cases, caused by a carbon buildup within an EGR valve. While this will not generally affect engine performance, you might have higher fuel consumption. Carbon buildup can be cleaned with EGR cleaner spray if not too extreme. Related Code: P0401
  • Engine Coolant Temperature Sensor  – A bad coolant temperature sensor is a fairly common fault with some Buicks. This will result in false temperature readings on your dashboard, causing rich engine operating conditions. In addition to the sensor, ensure the wiring is not damaged. Related Code: P0115
  • Oxygen sensor – O2 sensors may fail, triggering the check engine light to stay on and fuel efficiency to decrease. O2 sensors monitor oxygen levels in the exhaust, which helps the engine control unit determine the fuel mixture. An engine control unit can determine whether the fuel mixture is rich (less oxygen) or lean (more oxygen).

How to Reset  Buick Check Engine Light

The following steps will help you learn how to diagnose and reset the Buick check engine light.

For this procedure, you will need an OBD-II scanner. If you don’t have a scanner, you can purchase one online or stop by your local auto parts store to have the codes read free of charge.

  1. Park the Buick and turn off the ignition. Set the parking brakes.park buick diagnose check engien light
  2. Locate the OBD-II port under the dashboard and plugin your OBD-II scanner.obd 2 port used to diagnose buick check engine light service engine soon
  3. Turn on the ignition but do not start the engine.turn on buick igntion to read check engine fault codes cel ses
  4. Allow the scanner to turn on and communicate with the vehicle.diagnose check engine light
  5. Read the codes by pressing Read Codes or Read Fault Codes on your OBD-II scanner, depending on the scanner. Reach each code to learn more about possible codes. To clear the check engine light, you must fix the underlying problem before resetting the check engine light.

Fix all issues found in step five. Go to the main menu and select Clear Fault Codes, then OK.

The instructions worked in 1996, and newer vehicles such as Buick Enclave, Lesabre, Lacrosse, Verano, Regal, Lucerne, Rendezvous, Park Avenue, Allure, and Encore.

What does it mean when Buick Check Engine Light Flashing On and Off?

One problem that must never be ignored is a check engine light flashing, especially if accompanied by engine shaking and juddering. A check engine light going on and off intermittently signals an engine misfire, causing damage to the catalytic converter and other engine components.

It is not recommended to drive the vehicle if the check engine light is flashing. Common problems that can cause the Buick check engine light to flash on and off include old spark plugs, a bad ignition coil, a bad mass airflow sensor, or a clogged catalytic converter.


Buick check engine light on

Buick check engine light or service engine may soon come on for many reasons.

The first step is to check and tighten the gas cap. The check engine light may require a couple of days to reset. An OBD-II scanner can be used if you want to reset it as soon as you tighten the gas cap.

If the gas cap is not loose or damaged, the next step is to read the fault codes using an OBD-II scanner. You can take your car to a workshop for a complete diagnosis or get your scan tool. These devices come in all shapes, sizes, and prices.

We hope you find the Buick Check Engine Light Stays On guide helpful. Check these troubleshooting and repair guides for more help on your Buick.

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