Hi all,
Need some help with my grand daughter's 93 Grand Prix LE 3.1L vin T. The service soon light came on. Pulled code 42 (EST) bypass error. I cleared the code and started the engine, no service soon light. About 10 minutes later the service engine light came back on. Each I clear the code the same result. Start the engine no light about 5 to 10 minutes later the light comes on. What is the most common cause?


  • Thanks, Fletch