by Russell Krick Publisher The Goodheart-Willcox Co., Inc Tinley Park, Illinois © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only (16 Topics)  Computer-controlled emission system service  Emission maintenance reminder  Inspecting emission control systems  Exhaust gas analyzer  Emissions testing programs  Vacuum solenoid service © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  PCV system service  Evaporative emissions control system service  Thermostatic air cleaner system service  EGR system service  Air injection system service  Pulse air system service © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  Catalytic converter service  Oxygen sensor service  Emission control information sticker  OBD II drive cycle © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  Most emissions problems are caused by a malfunction in a system unrelated to the emission control system  fuel system  ignition system  exhaust system  computer control and electrical systems © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Scanning Emission Systems  Connect the scan tool to the data link connector  Check for diagnostic trouble codes (DTC’s)  Retrieve data © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Scanning Emission Systems © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Scan Tool Readout A DTC B Description C Possible causes © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  The circuit turns on a dash light to indicate the need for emission control system service  After repairs, the light must be turned off  Refer to the service manual for numerous procedures © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Voltmeter Testing  Probe between the signal wire and ground  Fast-idle the engine to ensure the sensor is hot  Record the minimum, maximum, and average voltages  The voltage should go below 200 mV, above 800 mV, and average around 450 mV © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Voltmeter Testing © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Oscilloscope Testing Probe between the signal wire and ground © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Oscilloscope Testing The sensor output should vary as shown © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Oscilloscope Testing Zirconia sensor waveform © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Dual Trace Scope If the waveforms are too similar, it indicates a faulty converter © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Emission Systems Wiring © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only O2 Sensor Replacement  Disconnect the negative battery cable  Unplug the sensor connector  Spray the threads with penetrating oil  Use a special sensor socket  Inspect for contamination © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only O2 Sensor © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only O2 Sensor Lazy sensor contaminated with carbon soot © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  The emission control information sticker contains important engine data  evaporative emissions information  schematics  specifications © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only Vehicle Emission Control Information © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only  Performed:  when the ECM has been disconnected from power  when the diagnostic trouble codes have been erased  to verify repairs, ensuring the DTC does not reoccur  before an emissions test © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only OBD II Drive Cycle Each vehicle and manufacturer has its own drive cycle © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only OBD II Drive Cycle  The vehicle is driven on a road test or dynamometer  To begin, coolant has to be below a specified temperature  The vehicle is driven through various conditions to allow computer to monitor all specified systems © Goodheart-Willcox Co., Inc Permission granted to reproduce for educational use only ... are caused by a malfunction in a system unrelated to the emission control system  fuel system  ignition system  exhaust system  computer control and electrical systems © Goodheart-Willcox Co.,... only  PCV system service  Evaporative emissions control system service  Thermostatic air cleaner system service  EGR system service  Air injection system service  Pulse air system service... use only (16 Topics)  Computer-controlled emission system service  Emission maintenance reminder  Inspecting emission control systems  Exhaust gas analyzer  Emissions testing programs  Vacuum