Here's how you can address the CEL after installing a new oxygen sensor:
1. Drive the van: The most important step. Drive the van for at least 50-100 miles under varying driving conditions (city and highway). This allows the OBD system to monitor the new sensor's performance and gather data.
2. The light might go out on its own: After sufficient driving, the OBD system may detect that the problem has been resolved and automatically turn off the CEL. This is the ideal scenario.
3. OBD I Scanner (if the light stays on): Your 1989 G20 uses a rudimentary OBD I system. You'll need an OBD I scanner specifically compatible with GM vehicles from that era. These scanners are often more basic than modern OBD II scanners. They'll read the diagnostic trouble code (DTC) stored in the computer's memory. The code will tell you *why* the light came on in the first place. If it's still related to the oxygen sensor and everything checks out after step 1, clearing the code with the scanner may be necessary.
4. Clearing the code (with a scanner): Once you've identified and addressed the problem (with a new sensor in this case), the scanner should have a function to clear the codes. This essentially resets the system's memory.
Important Considerations:
* Other potential problems: The oxygen sensor might not have been the only issue. A faulty oxygen sensor can sometimes be a symptom of a larger problem (like a bad catalytic converter). If the light stays on *after* driving sufficiently and having the code read, there might be another issue that needs attention.
* Incorrect sensor installation: Ensure the new oxygen sensor was installed correctly. A miswired or incorrectly seated sensor could trigger the CEL.
* Professional diagnosis: If you're uncomfortable working with OBD I systems, take your van to a qualified mechanic. They have the tools and expertise to properly diagnose and resolve the problem. Simply clearing the code without addressing the root cause won't fix the underlying issue.
In short, don't try to trick the system. Let the computer monitor the new sensor, and use a scanner to diagnose and resolve any remaining issues. Ignoring the light could lead to further damage to your engine.
