How do you reset the service engine soon light on 1994 Oldsmobile cutlass supreme?

The 1994 Oldsmobile Cutlass Supreme doesn't have a simple button or menu to reset the "Service Engine Soon" light (SES light, also known as the check engine light). That light indicates a problem detected by the car's onboard diagnostic system (OBD). You must address the underlying problem that triggered the light. Simply resetting the light without fixing the issue will only cause it to come back on.

Here's the process:

1. Get the diagnostic trouble code (DTC): You'll need to retrieve the code that the car's computer stored to understand the reason for the SES light. You have several options:

* OBD-II scanner: A relatively inexpensive OBD-II scanner (available at most auto parts stores) will read the code(s). This is the easiest and most recommended method. Keep in mind that a 1994 Cutlass Supreme uses an early OBD system, so a scanner compatible with both OBD I and OBD II is best.

* Paperclip method (less reliable): For older vehicles, some people try the "paperclip trick" to jump certain pins in the diagnostic connector (DLC) to read the codes via flashing lights. This method is much less reliable and may not work on all cars, especially not reliably on a '94 Cutlass. Information on this method is readily available online if you choose to try it but proceed with caution.

2. Identify the problem: Once you have the DTC, consult a repair manual (such as a Haynes or Chilton manual) or an online database like a Haynes Pro subscription to find out what the code means. This will tell you what system in your car is malfunctioning.

3. Fix the problem: Repair the identified issue. This could involve anything from replacing a sensor to a more extensive repair.

4. Clear the code (after repair): *After* you've fixed the problem, you can clear the code. Some OBD-II scanners have a "clear codes" function. Alternatively, disconnecting the car's battery's negative terminal for about 15-20 minutes will often reset the computer. Then, reconnect the battery and start the car. The light *should* be off. Drive the car for a few drive cycles (start the car, let it run for a while, turn it off, etc.) to ensure the computer confirms the problem is fixed.

Important Considerations:

* Ignoring the light is not recommended: Driving with the SES light on can lead to further damage and potential safety hazards.

* Professional help: If you're not comfortable diagnosing and repairing car problems yourself, take your Cutlass to a qualified mechanic.

Simply trying to reset the light without fixing the underlying mechanical or electrical fault is a temporary fix at best and could mask a serious problem. Diagnose and fix the issue first.