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Home >> Toyota >> 2015 >> Prius Four >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0300-P0657)) (Except Plug-In) >> SFI System >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1) [08/2014 - ] >> Typical Enabling Conditions
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Typical Enabling Conditions

Monitor runs whenever following DTCs not stored P0010 (Camshaft timing oil control valve assembly)
P0011 (VVT system - advance)
P0012 (VVT system - retard)
P0016 (VVT system - misalignment)
P0031, P0032, P101D (Air fuel ratio sensor heater)
P0037, P0038, P102D (Heated oxygen sensor heater)
P0102, P0103 (Mass air flow meter)
P0107, P0108 (Manifold absolute pressure)
P0115, P0117, P0118 (Engine coolant temperature sensor)
P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor)
P0125 (Insufficient coolant temperature for closed loop fuel control)
P0136, P0137, P0138, P0139, P013A, P0607 (Heated oxygen sensor)
P014C, P014D, P015A, P015B, P2195, P2196, P2237, P2238, P2239, P2252, P2253 (Air fuel ratio sensor)
P0171, P0172 (Fuel system)
P0300, P0301, P0302, P0303, P0304 (Misfire)
P0335 (Crankshaft position sensor)
P0340, P0342, P0343 (Camshaft position sensor)
P0351, P0352, P0353, P0354 (Igniter)
P0401 (EGR system (closed))
P219A, P219C, P219D, P219E, P219F (Air fuel ratio imbalance)
Auxiliary battery voltage 11 V or higher
Intake air temperature -10°C (14°F) or higher
Engine coolant temperature 75°C (167°F) or higher
Atmospheric pressure 76 kPa(abs) [570 mmHg(abs)] or higher
Idle OFF
Engine speed Less than 4000 rpm
Air fuel ratio sensor Activated
Fuel system status Closed loop
Engine load 10% or more, and less than 70%
All of the following conditions (a), (b) and (c) are met -
(a) Mass air flow 2.5 gm/sec or more, and less than 50 gm/sec
(b) Front catalyst temperature (estimated) 580°C (1076°F) or higher, and less than 770°C (1418°F)
(c) Rear catalyst temperature (estimated) 450°C (842°F) or higher, and less than 700°C (1292°F)