Conditions for Running the DTC

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

Before the ECM can report DTC P0420 failed, DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0101, P0102, P0103, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P0221, P0222, P0223, P0335, P0336, P0338, P167A, P167B, P2096, P2097, P2195, P2196, P2231, P2232, P2237, P2243, P2251, P2270, P2271, P2297, and P2626, must run and pass.
DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0101, P0102, P0103, P0117, P0118, P0121, P0122, P0123, P0125, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P0221, P0222, P0223, P0300, P0443, P0458, P0459, P0496, P167A, P167B, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095, P2096, P2097, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176, P2177, P2178, P2187, P2188, P2195, P2196, P2197, P2198, P2232, P2237, P2243, P2251, P2270, P2271, P2297, and P2626, are not set.
The air flow into the engine is between 10-42 g/s and not changing more than 8 g/s
The engine coolant temperature (ECT) at engine start-up is more than -9° C (-16° F).
The engine is operating for more than 320 seconds.
The engine is operating in Closed Loop.
The calculated TWC temperature is between 465° C (869° F) and 630° C (1,166° F) and steady.