P0421 Fault Code

P0421 NMHC Catalyst: Missing Substrate

Component / System

NMHC Catalyst - Missing Substrate

Monitor Strategy Description

Compare engine exhaust temperature rate of change to DOC temperature rate of change

Fault Limit

Ratio = Engine exhaust temperature rate of change DOC temperature rate of change < 1.5

Enable Conditions

Exhaust Gas Temperature Derivative > 3.75 °C/s or < -3.75 °C/s
Modeled DOC Outlet Temperature Derivative > 3.75 °C/s or < -3.75 °C/s
AHI Fuel Injection State Not Active
Number of sub evaluations 8

Disable Conditions

No Active DTC's:
P2226, P2229, P0110, P0112, P0115, P0117, P20DD, P20E0, P229E, P2200, P0105, P0108;P2031, P2322, P2084, P242C, P242A, P242B, P0545, P0544, P2080, P1130, P1133, P20DC,P20D0, P20CF

Time Required For P0421 DTC To Be Set

650 seconds (8 sub evaluations. 5 pass of 8 evaluations => PASS, 6 fail of 8 evaluations => FAIL)

MIL Illumination

2 Drive Cycles

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