Review on 🔒 Authentic Toyota Fuel Tank Cap Assembly (Part# 77300-53010) by Isaac Islam

Received code P0420. Much of the information available online suggests that the oxygen sensors need to be replaced or the computer flashed. There were many other opinions. After working with devices for over 40 years, I took the KISS method and started troubleshooting with the most economical and suspect component. gas cap. The fuel cap is responsible for equalizing the pressure in the fuel system. If the gasket (or O-ring) leaks, the pressure in the system will become uneven. The system computer regulates the factory-set exhaust gas values. If one of the many parameters does not meet the emission standard, you will receive an engine control display. Many conditions can cause trouble codes, but P0420, P0440, and P0442 are primarily due to a small leak in the fuel supply system. This doesn't mean that the fuel is actually running out, but that the air/fuel mixture the computer is getting on a regular basis is either lean or rich to compensate for uneven delivery. This is measured at post-combustion (exhaust) oxygen sensor locations in combination with computer monitoring and control functions. Having bought my '03 Corolla for a work car, I hardly noticed that a replacement cover was fitted, the Stant. The Stant cover pull ring had worn out to the point where it no longer provided the required seal in the fuel system and allowed air into the system. I believe in original equipment for most applications, not all. But in an application critical situation like the fuel system, I tend to think the OEM is better off with a replacement. This cover is exactly what was designed by the engineers on the machine. I haven't had a P0420 code since the replacement. I drive 500 km a week.