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Test Mode

NOTE: Check connector while it is connected unless otherwise specified. Be sure to check again from the beginning and proceed in order to prevent secondary trouble caused by repair work. When making checks with vacuum hose disconnected from the vacuum switch and the engine on, be sure to plug the hose.
  1. Start and warm engine until coolant temperature reaches 176° F (80° C). Turn engine and ignition switch off. Connect "Test Mode" connector. Turn ignition switch to "ON" position but DO NOT start engine.
  2. Ensure that ECS lamp turns on. If not, proceed to TEST MODE DIAGNOSTIC CHART "B". If lamp turns on, read indicated trouble code. If there is no trouble code indicated, replace ECM. If there is an indicated trouble code, ensure that it applies to the vehicle model.
  3. If trouble code does apply, proceed to TEST MODE DIAGNOSTIC CHART "A". If trouble code does not apply, check to see if selection code indicated is in the SELECTION CODE chart.
  4. If it is, ensure that its corresponding voltage applies to the vehicle. If it does, replace ECM. If not, make repairs as indicated by SELECTION CODE chart and SELECTION CODE CHART REPAIR PROCEDURES.
    Fig 1: Selection Code Chart
    G42828
    NOTE: B/R=Black/Red, R/Y=Red/Yellow and Lg=Light Green
    • X:  Connector should be open.
    • A:  Voltage greater than 4 volts should exist between ground terminal (14) of check connector II and check connector terminals which correspond with selection codes.
    • B:  Voltage less than 0.5 volt should exist between ground terminal (14) of check connector II and check connector terminals which correspond with selection codes.
    • C:  Voltage greater than 7 volts should exist between ground terminal (14) of check connector II and check connector terminals which correspond with selection codes.