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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 for Cressida and Supra 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 following manner: After the "start code", voltmeter needle will deflect a number of times between 2.5 volts and 5 volts at 0.6 second intervals. This is 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.
TCCS TROUBLE CODE IDENTIFICATION

Code No. (Pattern) Circuit Affected "CHECK ENGINE" Lamp
None System normal OFF
11 ECU power source OFF
12 RPM signal ON
14 Ignition signal ON
21 Oxygen sensor signal ON
22 Coolant temp. signal ON
23 Intake air temp. signal OFF
31 Airflow meter signal ON
32 Airflow meter signal ON
41 (1) TPS signal OFF
42 VSS signal OFF
43 Start signal OFF
51 (1) Switch Signal OFF
52 Knock sensor signal OFF
53 Knock CPU (ECU) ON
(1) A/C switch or Neutral/Start switch.