Note. To locate components, see COMPONENT LOCATIONS . For circuit reference, see WIRING DIAGRAMS . For connector terminal identification, see CONNECTOR IDENTIFICATION .
Home/Chevrolet/TrailBlazer/Chevrolet TrailBlazer I (2001-2006)/Repair manual/Testing & Diagnostics/DTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK…
Contents
Wiring diagrams Section: Testing & Diagnostics- Engine Controls - Basic Diagnostic Procedures: Overview
- Engine Controls - Basic Diagnostic Procedures: Diagnosis
- Engine Controls - Basic Diagnostic Procedures: Other
- Engine Controls - Basic Diagnostic Procedures - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline Engines: Overview
- Engine Controls - Basic Diagnostic Procedures - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline Engines: Diagnosis
- Engine Controls - Basic Diagnostic Procedures - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline Engines: Other
- Engine Control System - Trouble Shooting - No Codes - 4.2L: Diagnosis
- Engine Control System - Trouble Shooting - No Codes - 4.2L: Wiring
- Engine Control System - Trouble Shooting - No Codes - 4.2L: NVH
- Engine Control System - Trouble Shooting - No Codes - 4.2L: Other
- Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L: Overview
- Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L: Diagnosis
- Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L: Wiring
- Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L: NVH
- Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L: Other
- Engine Controls - System & Component Testing: Specifications
- Engine Controls - System & Component Testing: Overview
- Engine Controls - System & Component Testing: Diagnosis
- Engine Controls - System & Component Testing: Wiring
- Engine Controls - System & Component Testing: Component Locations
- Engine Controls - System & Component Testing: Other
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Specifications
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Overview
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Diagnosis
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Wiring
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Component Locations
- Engine Controls - System & Component Testing - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline: Other
- Engine Control System - Self-Diagnostics - 4.2L: Overview
- Engine Control System - Self-Diagnostics - 4.2L: Diagnosis
- Engine Control System - Self-Diagnostics - 4.2L: Maintenance
- Engine Control System - Self-Diagnostics - 4.2L: Component Locations
- Engine Control System - Self-Diagnostics - 4.2L: Other
- DTC P0013: CAMSHAFT POSITION "B" ACTUATOR CIRCUIT (BANK 1)
- DTC P0014: CAMSHAFT POSITION "B" TIMING OVER ADVANCED OR SYSTEM PERFORMANCE (BANK 1)
- DTC P0105: MAP SENSOR CIRCUIT - INSUFFICIENT ACTIVITY
- DTC P0107: MAP SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0112: IAT SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0113: IAT SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0122: TP SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0123: TP SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0125: EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL
- DTC P0128: COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE
- DTC P0130: HO2S CIRCUIT (BANK 1; SENSOR 1)
- DTC P0131: HO2S CIRCUIT - LOW VOLTAGE (BANK 1; SENSOR 1)
- DTC P0132: HO2S CIRCUIT - HIGH VOLTAGE (BANK 1; SENSOR 1)
- DTC P0133: HO2S CIRCUIT - SLOW RESPONSE (BANK 1; SENSOR 1)
- DTC P0134: HO2S CIRCUIT - INSUFFICIENT ACTIVITY (BANK 1; SENSOR 1)
- DTC P0135 OR P0141: HO2S HEATER CIRCUIT (BANK 1; SENSOR 1 OR 2)
- DTC P0137: HO2S CIRCUIT - LOW VOLTAGE (BANK 1; SENSOR 2)
- DTC P0138: HO2S CIRCUIT - HIGH VOLTAGE (BANK 1; SENSOR 2)
- DTC P0140: HO2S CIRCUIT - INSUFFICIENT ACTIVITY (BANK 1; SENSOR 2)
- DTC P0171: FUEL TRIM SYSTEM - LEAN (BANK 1)
- DTC P0172: FUEL TRIM SYSTEM - RICH (BANK 1)
- DTC P0201-P0206: FUEL INJECTOR CONTROL CIRCUIT
- DTC P0300: RANDOM/MULTIPLE CYLINDER MISFIRE DETECTED
- DTC P0301-P0306: CYLINDER MISFIRE DETECTED
- DTC P0326: KNOCK SENSOR 1 CIRCUIT - RANGE/PERFORMANCE (BANK 1)
- DTC P0327 OR P0332: KNOCK SENSOR 1 CIRCUIT - LOW VOLTAGE (BANK 1)
- DTC P0335: CRANKSHAFT POSITION SENSOR "A" CIRCUIT
- DTC P0336: CRANKSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PERFORMANCE
- DTC P0340: CAMSHAFT POSITION SENSOR "A" CIRCUIT (BANK 1)
- DTC P0341: CAMSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PERFORMANCE (BANK 1)
- DTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1)
- DTC P0440: EVAPORATIVE EMISSION CONTROL SYSTEM
- DTC P0442: EVAP SYSTEM - SMALL LEAK DETECTED
- DTC P0446: EVAP VENT VALVE CONTROL CIRCUIT
- DTC P0452: EVAP SYSTEM PRESSURE SENSOR - LOW INPUT
- DTC P0453: EVAP SYSTEM PRESSURE SENSOR - HIGH INPUT
- DTC P0502: VEHICLE SPEED SENSOR - LOW OUTPUT
- DTC P0503: VEHICLE SPEED SENSOR - INTERMITTENT
- DTC P0506: IDLE CONTROL SYSTEM - LOW RPM
- DTC P0507: IDLE CONTROL SYSTEM - HIGH RPM
- DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 OR P2610: PCM MEMORY
- DTC P1120: THROTTLE POSITION SENSOR 1 CIRCUIT
- DTC P1133: HO2S CIRCUIT - INSUFFICIENT SWITCHING (SENSOR 1)
- DTC P1134: HO2S TRANSITION TIME RATIO (BANK 1; SENSOR 1)
- DTC P1137: HO2S CIRCUIT - LEAN SYSTEM (BANK 1; SENSOR 2)
- DTC P1138: HO2S CIRCUIT - HIGH VOLTAGE (BANK 1; SENSOR 2)
- DTC P1171: FUEL SYSTEM LEAN DURING ACCELERATION
- DTC P1220: THROTTLE POSITION SENSOR 2 CIRCUIT
- DTC P1221: THROTTLE POSITION SENSORS 1 & 2 CORRELATION
- DTC P1271: ACCELERATOR PEDAL POSITION SENSORS 1 & 2 CORRELATION
- DTC P1275: ACCELERATOR PEDAL POSITION CIRCUIT (SENSOR 1)
- DTC P1280: ACCELERATOR PEDAL POSITION CIRCUIT (SENSOR 2)
- DTC P1336: CRANKSHAFT SYSTEM VARIATION NOT LEARNED
- DTC P1345: CRANKSHAFT/CAMSHAFT POSITION SENSOR CORRELATION
- DTC P1380: MISFIRE DETECTED - ROUGH ROAD DATA NOT AVAILABLE
- DTC P1381: MISFIRE DETECTED - NO COMMUNICATION WITH BRAKE CONTROL MODULE
- DTC P1441: EVAP SYSTEM FLOW DURING NON-PURGE
- DTC P1512: INTAKE MANIFOLD RUNNER CONTROL STUCK CLOSED (BANK 1)
- DTC P1514: THROTTLE BODY PERFORMANCE
- DTC P1515: COMMANDED VS. ACTUAL THROTTLE POSITION PERFORMANCE (PCM)
- DTC P1516: COMMANDED VS. ACTUAL THROTTLE POSITION PERFORMANCE (TAC MODULE)
- DTC P1633: IGNITION 0 CIRCUIT PERFORMANCE
- DTC P1635: 5-VOLT REFERENCE "A" CIRCUIT
- DTC P1639: 5-VOLT REFERENCE "B" CIRCUIT
- DTC P1682: DRIVER 5; LINE 2
- Engine Control System - Self-Diagnostics - 5.3L: Overview
- Engine Control System - Self-Diagnostics - 5.3L: Diagnosis
- Engine Control System - Self-Diagnostics - 5.3L: Maintenance
- Engine Control System - Self-Diagnostics - 5.3L: Wiring
- Engine Control System - Self-Diagnostics - 5.3L: Component Locations
- Engine Control System - Self-Diagnostics - 5.3L: NVH
- Engine Control System - Self-Diagnostics - 5.3L: Other
- DTC P0101: MASS AIR FLOW SENSOR PERFORMANCE
- DTC P0102: MASS AIR FLOW SENSOR CIRCUIT - LOW FREQUENCY
- DTC P0103: MASS AIR FLOW SENSOR CIRCUIT - HIGH FREQUENCY
- DTC P0106: MAP SYSTEM PERFORMANCE
- DTC P0107: MAP SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0112: IAT SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0113: IAT SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0116: ECT SENSOR PERFORMANCE
- DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE
- DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE
- DTC P0120: TP SENSOR CIRCUIT
- DTC P0125: EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL
- DTC P0128: ECT LESS THAN THERMOSTAT REGULATING TEMPERATURE
- DTC P0131: HO2S CIRCUIT - LOW VOLTAGE - BANK 1, SENSOR 1 & DTC P0151: HO2S CIRCUIT - LOW VOLTAGE - BANK 2, SENSOR 1
- DTC P0132: HO2S CIRCUIT - HIGH VOLTAGE - BANK 1, SENSOR 1 & DTC P0152: HO2S CIRCUIT - HIGH VOLTAGE - BANK 2, SENSOR 1
- DTC P0133: HO2S CIRCUIT - SLOW RESPONSE - BANK 1, SENSOR 1 & DTC P0153: HO2S CIRCUIT - SLOW RESPONSE - BANK 2, SENSOR 1
- DTC P0134: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 1, SENSOR 1 & DTC P0154: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 2, SENSOR 1
- DTC P0135: HO2S HEATER CIRCUIT - BANK 1, SENSOR 1, DTC P0155: HO2S HEATER CIRCUIT - BANK 2, SENSOR 1, DTC P0141: HO2S HEATER CIRCUIT - BANK 1, SENSOR 2 & P0161: HO2S HEATER CIRCUIT - BANK 2, SENSOR 2
- DTC P0137: HO2S CIRCUIT - LOW VOLTAGE - BANK 1, SENSOR 2 & DTC P0157: HO2S CIRCUIT - LOW VOLTAGE - BANK 2, SENSOR 2
- DTC P0138: HO2S CIRCUIT - HIGH VOLTAGE - BANK 1, SENSOR 2 & DTC P0158: HO2S CIRCUIT - HIGH VOLTAGE - BANK 2, SENSOR 2
- DTC P0140: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 1, SENSOR 2 & DTC P0160: HO2S CIRCUIT - INSUFFICIENT ACTIVITY - BANK 2, SENSOR 2
- DTC P0171: FUEL TRIM SYSTEM LEAN - BANK 1 & DTC P0174: FUEL TRIM SYSTEM LEAN - BANK 2
- DTC P0172: FUEL TRIM SYSTEM RICH - BANK 1 & DTC P0175: FUEL TRIM SYSTEM RICH - BANK 2
- DTC P0200: FUEL INJECTOR CONTROL CIRCUIT
- DTC P0220: THROTTLE POSITION SENSOR 2 CIRCUIT
- DTC P0230: FUEL PUMP CONTROL RELAY CIRCUIT
- DTC P0300: ENGINE MISFIRE DETECTED
- DTC P0315: CRANKSHAFT POSITION SENSOR VARIATION NOT LEARNED
- DTC P0325: KNOCK SENSOR MODULE CIRCUIT
- DTC P0327: KNOCK SENSOR CIRCUIT - LOW VOLTAGE - SENSOR 1 & DTC P0332: KNOCK SENSOR CIRCUIT - LOW VOLTAGE - SENSOR 2
- DTC P0335: CRANKSHAFT POSITION SENSOR CIRCUIT
- DTC P0336: CRANKSHAFT POSITION SENSOR CIRCUIT PERFORMANCE
- DTC P0341: CAMSHAFT POSITION SENSOR CIRCUIT PERFORMANCE
- DTC P0342: CAMSHAFT POSITION SENSOR - SIGNAL LOW
- DTC P0343: CAMSHAFT POSITION SENSOR - SIGNAL HIGH
- DTC P0351-P0358: IGNITION CONTROL CIRCUIT
- DTC P0420: TWC SYSTEM - LOW EFFICIENCY - BANK 1 & DTC P0430: TWC SYSTEM - LOW EFFICIENCY - BANK 2
- DTC P0442: EVAP SYSTEM - SMALL LEAK
- DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT
- DTC P0446: EVAP VENT CONTROL CIRCUIT
- DTC P0449: EVAP VENT SOLENOID VALVE CONTROL CIRCUIT
- DTC P0452: FUEL TANK PRESSURE SENSOR - LOW VOLTAGE
- DTC P0453: FUEL TANK PRESSURE SENSOR - HIGH VOLTAGE
- DTC P0455: EVAP SYSTEM LEAK DETECTED - GROSS LEAK/NO FLOW
- DTC P0496: EVAP SYSTEM HIGH PURGE FLOW
- DTC P0506: IDLE CONTROL SYSTEM - LOW RPM
- DTC P0507: IDLE CONTROL SYSTEM - HIGH RPM
- DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 & P2610: PCM MEMORY
- DTC P0641: 5-VOLT REFERENCE CIRCUIT OUT OF RANGE
- DTC P0650: MIL CONTROL CIRCUIT
- DTC P0651: SENSOR REFERENCE VOLTAGE CIRCUIT
- DTC P1106: MAP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE
- DTC P1107: MAP SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE
- DTC P1111: IAT SENSOR CIRCUIT - INTERMITTENT HIGH VOLTAGE
- DTC P1112: IAT SENSOR CIRCUIT - INTERMITTENT LOW VOLTAGE
- DTC P1114: ECT SENSOR CIRCUIT - INTERMITTENT LOW VOLTAGE
- DTC P1115: ECT SENSOR CIRCUIT - INTERMITTENT HIGH VOLTAGE
- DTC P1125: ACCELERATOR PEDAL POSITION SENSORS OUT OF RANGE OR DISAGREE
- DTC P1133: HO2S CIRCUIT - INSUFFICIENT SWITCHING - BANK 1, SENSOR 1 & DTC P1153: HO2S CIRCUIT - INSUFFICIENT SWITCHING - BANK 2, SENSOR 1
- DTC P1380: EBCM DTC DETECTED ROUGH ROAD DATA UNSTABLE
- DTC P1381: MISFIRE DETECTED - NO EBCM/PCM SERIAL DATA
- DTC P1514: CALCULATED VS ACTUAL AIRFLOW CORRELATION HIGH
- DTC P1515: PREDICTED VS ACTUAL THROTTLE POSITION CORRELATION ERROR
- DTC P1516: PREDICTED VS ACTUAL THROTTLE POSITION CORRELATION ERROR
- DTC P1518: TAC MODULE SERIAL DATA FAULT
- DTC P2108: TAC MODULE PROCESSOR FAULT
- DTC P2120: APP SENSOR 1 CIRCUIT MALFUNCTION
- DTC P2121: APP SENSOR CIRCUITS OUT OF CORRELATION
- DTC P2125: APP SENSOR 2 CIRCUIT MALFUNCTION
- DTC P2135: TP SENSOR SIGNALS 1 & 2 DISAGREE OR OUTSIDE PREDETERMINED RANGE
- Abbreviations
- Accessories Control Systems
- Accessory Drive Belts
- Adjustments
- Airbag
- Anti-Lock/traction Control
- Application
- Automatic HVAC System
- Automatic Trans
- Axle Shafts
- Basic Trouble Shooting
- Body Electrical
- Brakes
- Charging System
- Check Lists
- Communication Devices
- Computer Relearn
- Cooling Fan
- Cooling System (Mechanical)
- Cruise Control Systems
- Diagnostic Connector Locations
- Differentials & Drive Axles
- Door Locks & Anti-Theft Systems
- Drive Cycles
- Driveline/axles
- Driveshaft & Universal Joints
- DTC Index
- Electrical
- Electrical Component Locations
- Electronic Suspension
- Emission Applications
- Engine
- Engine Performance
- Entertainment Systems
- Exhaust
- Exterior Body Panels
- Exterior Lights
- Exterior/interior Trim
- Frames, Subframes & Crossmembers
- Fuses & Circuit Breakers
- Gauges & Instrument Panels
- General Servicing - All Makes
- Heated Glass/defoggers
- Hoist/jack
- Horns
- Identification
- Ignition Switch/steering Lock
- Manual & Power Steering
- Manual HVAC System
- Mechanical
- Mechanical - Hydraulic
- Memory Modules
- Metric Conversions
- Mode 6
- Oem General Information
- Removal & Installation
- Reset Procedures
- Restraints
- Restraints Control Systems
- Rpo Codes
- Seats
- Sensor Range Charts
- Specifications
- Starter
- Steering
- Sun Roof/t-Top/convertible Top
- Suspension Front
- Suspension Rear
- Testing & Diagnostics
- Theory & Operation
- Traction Control Disable
- Transfer Case
- Transmission
- Wheel & Tire System
- Wheel Alignment
- Wiper/washer Systems