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A/T Gear Position Signal

NOTE: This signal informs PCM when transmission is in Park or Neutral.
NOTE: For A/T gear position signal testing on Accord, CR-V and Odyssey, see DTC P1705 or P1706: A/T GEAR POSITION SWITCH in appropriate SELF-DIAGNOSTICS article.
  1. Turn ignition on. Observe A/T position indicator on instrument panel while selecting each gear position separately. If A/T position indicator functions properly, go to next step. If A/T position indicator does not function properly, see appropriate article in AUTOMATIC TRANSMISSIONS.
  2. Turn ignition off. Disconnect instrument cluster 16-pin (Prelude) or 14-pin (Civic) connector. Disconnect Transmission Control Module (TCM) 26-pin connector. On Prelude, TCM is located in passenger side footwell, next to PCM. See COMPONENT LOCATIONS . On Civic, TCM is located behind passenger side kick panel. On all models, turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 9 (Brown/Black wire) and 32-pin connector "C" terminal No. 29 (Light Green wire). See PIN VOLTAGE CHARTS article. If about 5 volts does not exist, go to next step. If about 5 volts exists, go to step  4.
  3. Turn ignition off. Disconnect PCM 31-pin connector "C". Check for continuity between ground and PCM 31-pin connector "C" terminal No. 29 (Light Green wire. See PIN VOLTAGE CHARTS article. If continuity exists, repair short in Light Green wire between PCM 31-pin connector "C" and instrument cluster. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. On Prelude, see SUBSTITUTING PCM in SELF-DIAGNOSTICS - INTRODUCTION article. If symptom or indication goes away, replace original PCM.
  4. Turn ignition off. Reconnect instrument cluster and TCM connectors. Place transmission in Park or Neutral position. Start engine. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 9 (Brown/Black wire) and PCM 31-pin connector "C" terminal No. 29 (Light Green wire). If less than one volt exists, go to next step. If less than one volt does not exist, repair open in Light Green wire between PCM 31-pin connector "C" and instrument cluster.
  5. Measure voltage between PCM 32-pin connector "A" terminal No. 9 (Brown/Black wire) and terminal PCM 31-pin connector "C" terminal No. 29 (Light Green wire) with transmission in any position except Park or Neutral. If battery voltage on Civic, or 5 volts or more on Prelude exists, A/T gear position signal is okay. If specified voltage does not exist, repair short in Light Green wire between PCM 31-pin connector "C" and instrument cluster. See WIRING DIAGRAMS article.
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