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Automatic Transmission Shift Position Signal

  1. While watching shift indicator, shift transmission gear to each position. If shift indicator lights up correctly for all positions, turn ignition off. Connect PGM-FI test harness between ECU and ECU connectors. Disconnect connector "B" from main harness only; DO NOT  disconnect from ECU. Turn ignition on. Measure voltage between ECU terminals B7 (positive) and A26 (negative). If voltage is not around 10 volts, substitute a known good ECU, and recheck voltage.
  2. If voltage is about 10 volts, reconnect connector "B" to main wiring harness. Place transmission in Neutral. Measure voltage between terminals B7 (positive) and A26 (negative). If voltage is more than 1 volt, repair open in Light Green wire between ECU B7 and connector.
  3. If voltage is less than 1 volt, place transmission in Park, and measure voltage between terminals B7 (positive) and A26 (negative). If voltage is more than one volt, replace shift position signal.
  4. If voltage is not more than one volt, place transmission in Drive, and measure voltage between terminals B7 (positive) and A26 (negative). If voltage is not about 10 volts, repair short in Light Green wire between ECU terminal B7 and combination meter. If voltage is about 10 volts, shift position signal is okay.
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