Here's what code 18 likely means in your context:
* Heated Oxygen Sensor Circuit Malfunction: The heated O2 sensor is crucial for accurate fuel mixture control, especially during cold starts. Code 18 suggests a problem with the sensor's heating element or the wiring/circuit supplying power to it. This could be a faulty sensor, a blown fuse, damaged wiring, or a problem with the sensor's connector.
Troubleshooting Steps:
1. Check the OBD-I system documentation: Your car's repair manual or a GM OBD-I code chart will provide the most accurate definition of code 18 for your specific vehicle. Different years and models can have slight variations.
2. Inspect the Oxygen Sensor: Visually inspect the O2 sensor and its wiring harness for any signs of damage, corrosion, or loose connections. Pay close attention to the connector.
3. Check the Fuse: Locate the fuse for the heated O2 sensor in your fuse box and verify it's not blown.
4. Check Wiring: Carefully examine the wiring leading to the O2 sensor for any breaks, shorts, or chafing.
5. Measure the sensor's resistance (if you have a multimeter): The resistance of the heating element should fall within a specific range, check your repair manual for this information.
6. Test the O2 sensor: This is best done with a dedicated O2 sensor tester. A multimeter can also give you some basic readings, but a dedicated tester is more accurate.
7. Replace the O2 sensor: If the sensor, wiring, or fuse is found to be faulty, it's generally best to replace the entire sensor. This is a fairly common repair. Be sure to get a replacement sensor that is specifically designed for your 1993 Pontiac Bonneville SSEi.
Important Considerations:
* Supercharger Implications: The supercharger increases the stress on the engine and its components, including the O2 sensor. A malfunctioning O2 sensor can lead to poor performance, reduced fuel efficiency, and potentially damage to the engine.
* OBD-I Limitations: OBD-I systems are less sophisticated than modern OBD-II systems. The code might not pinpoint the exact problem with complete certainty. Careful diagnostic steps are crucial.
If you're not comfortable working on your car yourself, it's best to take it to a qualified mechanic for diagnosis and repair. They have the tools and expertise to accurately diagnose the problem and fix it efficiently.
