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Diagnostic Code Output

  1. After entering diagnostic mode, the voltmeter needle should indicate 5 volts for 2 seconds; then 2.5 volts for 2 seconds. This code ("start code") signifies the start of diagnostic code output. See Fig 1.
    Fig 1: Example of Trouble Code Output Output is in form of voltmeter needle fluctuations.
    G42144Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. If no trouble codes are stored in ECU memory, the "start code" will be displayed, followed by the "system normal" code. The "system normal" code consists of a series of needle fluctuations between 5 volts and 2.5 volts at 0.6 second intervals.
  3. Trouble codes are displayed in the following manner: After the "start code", the voltmeter needle will deflect a number of times between 2.5 volts and 5 volts at 0.6 second intervals. This is the first digit of the trouble code.
  4. The needle will then indicate 2.5 volts for 2 seconds ("separator code"). Next, the needle will fluctuate between 2.5 volts and 0 volt at 0.6 second intervals. This is the second digit of the trouble code.
  5. Trouble codes will be displayed from lowest to highest numbered code. Output of the diagnostic codes will continue as long as the diagnostic mode is activated. A "separator code" follows display of first and second digit of trouble codes, and separates each trouble code. A "start code" will be displayed at the beginning of each pass through the output.