P0141 and P0300 Fault Codes on 1997 GMC Safari Van with 79,000 Miles
I have a 1997 GMC Safari van with 79,000 miles and a 5.7L engine. The vehicle is currently displaying both fault codes P0141 and P0300. I'm seeking advice on how to diagnose and resolve these issues, especially since the P0141 code relates to the post-catalyst oxygen sensor (Bank 1, driver's side). Before replacing any sensors, it's important to verify wiring connections and ensure proper voltage and ground signals. Any insights or troubleshooting steps would be greatly appreciated.
When was the last time a tune-up was performed? Additionally, the post-catalyst oxygen sensor (Bank 1, driver's side) is likely faulty. Before replacing it, check all wiring and connections for proper voltage and ground continuity. Always verify these before assuming sensor failure. Good luck—please update us on your findings.