GM Service Manual Online
For 1990-2009 cars only

System

DTCs Required to Set System Status to YES

Catalyst

DTC P0420 Catalyst System Low Efficiency

EGR

DTC P0401 EGR Flow Insufficient

DTC P0402 EGR Flow Excessive

DTC P0403 EGR Solenoid Control Circuit

EVAP

DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge

DTC P0442 EVAP System No Flow During Purge

DTC P0443 EVAP Purge Solenoid Control Curcuit

DTC P0446 EVAP Vent System Performance

DTC P0449 EVAP Vent Solenoid Control Circuit

DTC P0455 Evaporative Emission (EVAP) System Leak

DTC P0496 EVAP System Flow During Non‐Purge

DTC P2026 Fuel Vapor Temperature Sensor Circuit Low Voltage

DTC P2027 Fuel Vapor Temperature Sensor Circuit High Voltage

Oxygen Sensor

DTC P0131 HO2S Circuit Low Voltage Sensor 1

DTC P0132 HO2S Circuit High Voltage Sensor 1

DTC P0133 HO2S Slow Response Sensor 1

DTC P0134 HO2S Insufficient Activity Sensor 1

DTC P0137 HO2S Circuit Low Voltage Sensor 2

DTC P0138 HO2S Circuit High Voltage Sensor 2

DTC P0140 HO2S Insufficient Activity Sensor 2

Oxygen Sensor Heater

DTC P0031 HO2S Heater Circuit Low Voltage Sensor 1

DTC P0032 HO2S Heater Circuit High Voltage Sensor 1

DTC P0037 HO2S Heater Circuit Low Voltage Sensor 2

DTC P0038 HO2S Heater Circuit High Voltage Sensor 2