Entering Diagnostic Mode

1984 Toyota Cressida 4D WagonSECTION Entering Diagnostic Mode
  1. Prior to entering diagnostic mode, the following conditions must be met: Engine must be at normal operating temperature, battery voltage above 11 volts, transmission in "P" or Neutral, throttle valve fully closed and A/C off.
  2. Turn ignition on, but DO NOT  start engine. Remove rubber cap from "CHECK ENGINE" connector, near distributor. Using a jumper wire, jumper both terminals of the connector together. See Fig 1.
    Fig 1: Jumpering "CHECK ENGINE" Connector Insert jumper wire in "CHECK ENGINE" connector.
    G42142Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Remove rubber cap from "EFI" service connector, located near battery. Using an adapter harness (SST 09842-14010), connect adapter to service connector. Connect positive probe of an analog voltmeter to Red lead of adapter harness and negative probe to Black lead. See Fig 2.
Fig 2: Connecting Voltmeter to "EFI" Connector Make sure leads are properly connected.
G42143Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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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.