Closed Loop Emission System

• Description
• Operation
  • Notes
  • Input Sensors
    • Altitude Switch
    • Coolant Temperature Sensor
    • ECM Relay
    • Idle Switch
    • Inlet Air Temperature Sensor
    • Oxygen (O2) Sensor
    • Speed Sensor
    • Tachometer Signal
    • WOT Switch
  • Output Components
    • Air Switching Valve (ASV)
    • Duty Solenoid
    • Early Fuel Evaporation (EFE) Relay
    • Fuel-Cut Solenoid
    • Purge Solenoid
  • Electronic Control Module
    • Notes
    • Inhibit Mode
    • Enrichment Mode
    • Open Loop Mode
    • Closed Loop Mode
• Diagnosis & Testing
  • Diagnostic Circuit Check
    • Notes
    • Clearing Trouble Codes
    • Exiting Diagnostic Mode
  • System Performance Check
    • Notes
    • TEST 1 (Dwell Fixed Under 10 Degrees)
    • TEST 2 (Dwell Fixed Between 10-80 Degrees)
    • TEST 3 (Dwell Fixed Over 80 Degrees)
    • TEST 4 (Idle & WOT Switch Circuit Check)
    • TEST 5 ("Check Engine" Light Inoperative)
    • TEST 6 (Will Not Flash Code 12)
  • Trouble Codes
    • CODE 12 (No Reference Pulse to ECM)
    • CODE 13 (Open O2 Sensor Circuit)
    • CODE 14 (Shorted Coolant Sensor Circuit)
    • CODE 15 (Open Coolant Sensor Circuit)
    • CODE 21 (Idle Switch Circuit Open or WOT Switch Circuit Shorted)
    • CODE 22 & 51 (Fuel-Cut Solenoid Circuit Failure)
    • CODE 23 & 54 (Duty Solenoid Circuit Failure)
    • CODE 25 & 53 (AIR Vacuum Switching Valve (VSV) Failure)
    • CODE 26 & 27 (Vacuum Switching Valve (VSV) Canister Purge Failure)
    • CODE 31 (No Reference Signal)
    • CODE 32 (EGR System Failure & Sensor Circuit Failure)
    • CODE 34 (EGR Temperature Sensor or Harness Failure)
    • CODE 44 (O2 Sensor Lean Condition)
    • CODE 45 (O2 Sensor Rich Condition)
    • CODE 52 & 55 (Internal ECM Problem)
  • Air, Temperature, And Idle Testing
    • AIR Management System
    • Coolant Temperature Sensor
    • Duty Solenoid
    • Idle & WOT Switches
    • Inlet Air Temperature Sensor
• Wiring Diagrams