Conditions For Running DTC

• DTCs P0105, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0204, P0217, P0300, P0301-P0304, P0326, P0327, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0480, P0481, P0500 (M/T only), P0502, P0503, P0506, P0507, P0562, P0563, P0601, P0602, P1133, P1137, P1138, P1171, P1336, P1441, P1621, P2135 are not set.
• Engine has been running more than 10 minutes after the throttle has moved.
• Vehicle is in a Closed Loop operation.
• Vehicle has been driven at more than 1200 RPM for more than 45 seconds.
• Calculated catalytic temperature is 707-1392°F (375-750°C).
• Calculated air flow parameter is less than 8 g/s.
• ECT is 158-257°F (70-125°C).
• IAT is -6 and 176°F (-21 and 125°C).
• Barometric pressure is more than 72 kPa.
• Ignition voltage is more than 9 volts.
• Engine must be at idle and within -75 to 150 RPM of desired idle speed.

This DTC P0420 is sampled once at an idle when the above conditions are met. If the first test fails, the PCM will take more samples during the current ignition cycle or may take samples for up to six ignition cycles. The extra sampling is to ensure that a converter has failed, and has not been temporarily poisoned.