1998 Chevrolet Trans AM O2 Sensor Fault Codes P0131, P0137, P0151, P0157 - Possible Cause After Air Check Valve Replacement
Hello everyone! I recently purchased a 1998 Chevrolet Trans AM Firebird and am experiencing multiple O2 sensor fault codes: P0131, P0137, P0151, and P0157. These codes began appearing after I replaced the passenger-side air check valve located in the exhaust manifold. Is it possible that all four oxygen sensors are faulty? Or could there be another issue—such as a leak or incorrect installation—related to the air check valve replacement? I'm looking for expert advice on diagnosing this problem and determining whether the fault codes are due to sensor failure or a system leak. Thanks in advance for any insights!
No, it's unlikely all four oxygen sensors are faulty. The air check valve is installed in the exhaust manifold and if improperly reinstalled or if there’s a leak, it can cause incorrect oxygen sensor readings. A leak in the intake or exhaust system may lead to inaccurate O2 sensor signals, triggering these fault codes. Check for proper sealing and ensure no hoses are crossed or misconnected.