1998 Accord LX 2.2L VTEC Manual Transmission - P0141 Code Recurring After Oxygen Sensor Replacement
I've been experiencing a recurring P0141 code on my 1998 Accord LX with the 2.2L VTEC engine and manual transmission. My catalytic converter is only about 5 months old, and both oxygen sensors have recently been replaced. I replaced Bank 1 Sensor 2 (located in the catalytic converter), which initially caused the check engine light to turn off. After a 40-minute drive—long enough for all test cycles to complete—the code returned. Now, my idle is rough, and I suspect the issue may not be with the oxygen sensor itself. I'm wondering if the ECM (Engine Control Module) could be faulty or if there's another underlying cause. The P0141 code specifically points to a problem with Bank 1 Sensor 2 in the catalytic converter system. I haven't checked the code again since, but I believe it will likely reappear. I also previously had an EVAP system fault that has now cleared after replacing the relevant component—this suggests the issue may be isolated to the oxygen sensor or its associated circuitry. I'd like to identify the root cause before replacing more parts. Any guidance on how to diagnose this properly would be greatly appreciated.
It's unlikely that the ECM is faulty. First, check the O2 sensor heater circuit for proper power and ground connections. Also verify whether the oxygen sensors were installed by a dealer or an aftermarket supplier—aftermarket parts can sometimes cause compatibility issues or incorrect readings.