To figure out what's causing the light, you'll need to:
* Get the codes: 1989 Buicks use a rudimentary OBD system. You'll likely need to use a method called "jump testing" to retrieve diagnostic trouble codes (DTCs). This involves briefly connecting two wires in the diagnostic connector (usually under the dashboard, but its location may vary slightly on your model year) while monitoring the check engine light's flashing pattern. The flashing sequence represents a DTC. You'll need a Buick-specific repair manual or a reliable online resource for your year and model to interpret these codes.
* Use a scan tool (optional but helpful): While jump testing is possible, a scan tool designed for OBD-I systems (pre-OBD-II) will make reading the codes much easier.
* Common Causes (General, not specific to your code): While you need the codes for a diagnosis, some common causes for an SES light in older cars include:
* Oxygen sensor: A faulty oxygen sensor is a frequent culprit.
* Mass airflow sensor (MAF sensor): If equipped, a malfunctioning MAF sensor can trigger the light.
* Throttle position sensor (TPS): Problems here affect fuel delivery and engine timing.
* Catalytic converter: A failing catalytic converter can cause issues.
* Ignition system problems: Issues with spark plugs, wires, distributor cap, or rotor can trigger the light.
* Loose gas cap: Surprisingly, a loose or faulty gas cap can trigger the SES light due to evaporative emissions.
Important Note: Driving with a malfunctioning engine can cause further damage. While you try to diagnose the issue, avoid harsh driving conditions and consider driving the car as little as possible until the problem is resolved. Getting the codes is the crucial first step. Once you have them, you can consult repair manuals or online forums for Buick Rivieras of that year to get a better understanding of the potential problem.
