Inspection/Maintenance System DTCS: Description

2001 Chevrolet Chevy Express G3500, Van Passenger Extended, 6.5 FSECTION Description
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The following DTCs are required to set system status to YES:

Catalyst System 

  • P0420

    TWC System Low Efficiency (Bank 1)

EGR System 

  • P0401

    EGR System
  • P0404

    EGR System
  • P0405

    EGR Sensor Circuit - Low Voltage
  • P1404

    EGR System (Valve No. 2)

EVAP System 

  • P0440

    EVAP System
  • P0442

    EVAP System - Leak Detected
  • P0446

    EVAP Canister Vent Blocked
  • P1441

    EVAP System Flow During Non-Purge

Oxygen Sensor System 

  • P0133

    HO2S Slow Response
  • P0140

    HO2S Circuit Insufficient Activity (Bank 1; Sensor 2)
  • P1133

    HO2S Insufficient Switching (Bank 1; Sensor 1)
  • P1134

    HO2S Transition Time Ratio (Bank 1; Sensor 1)

Oxygen Sensor Heater System 

  • P0135

    HO2S Heater Performance
  • P0141

    HO2S Heater Performance (Bank 1; Sensor 2)

Diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.