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Code 51: Neutral Position Switch - M/T

NOTE: Refer to illustration for ECU connector and terminal identification. See Figure .
  1. Turn ignition on. Measure voltage between ECU connector E29, terminal No. 16 (backprobe) and ground. With transmission selector lever in Neutral, 10-14 volts should be present. With transmission selector lever in any position but Neutral, zero voltage should be present. If voltages are to specification, repair ECU connector or replace ECU. If voltages are not to specification, go to next step.
  2. Turn ignition off. Disconnect 2-pin transmission harness connector. Measure resistance between connector harness terminals. In Neutral, at least one megohm should be present. With transmission selector lever in any position but Neutral, less than 10 ohms should be present. If resistances are not to specification, replace neutral position switch. If resistances are to specification, go to next step.
  3. Turn ignition on. Measure voltage between neutral position switch connector terminal No. 1 (Light Green/Yellow wire) and ground. At least 10 volts should be present. If voltage is not to specification, repair power supply circuit. If voltage is to specification, repair or replace harness between ECU and neutral position switch.
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