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Home >> Geo >> 1993 >> Storm Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Engine Sensors & Switches >> Park/Neutral Position Switch
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Park/Neutral Position Switch

  1. Park/neutral position switch contacts are closed in Park or Neutral and open in all other gears. Park/neutral position switch provides current to neutral relay when in Park or Neutral. Neutral relay contacts close, causing signal voltage on White/Blue wire from ECM to decrease. ECM monitors signal voltage and determines if vehicle is in Park or Neutral when signal voltage decreases to less than one volt.
  2. To check switch and circuit operation, turn ignition on with engine off. Install scan tester. Scan tester should display P/N with transaxle in Park or Neutral and R-D-L in all other gears.
  3. If scan tester displayed correctly, park/neutral position switch and wiring circuit are okay. If scan tester does not display correctly, disconnect electrical connector from neutral relay. Neutral relay is located in relay box in right corner of engine compartment, near strut tower.
    CAUTION: Automatic transaxle Electronic Control Unit (ECU) on 4-speed transaxle may be mounted on left side of steering column. DO NOT  confuse ECU with ECM. ECM contains 24-pin and 32-pin connectors; ECU contains 16-pin and 20-pin connectors.
  4. With transaxle in Park or Neutral, tester should display P/N. If P/N is displayed, go to next step. If P/N is not displayed, White/Blue wire between neutral relay and ECM is grounded or ECM is defective. ECM is located under left side of instrument panel, left of steering column.
  5. Using fused jumper wire, ground White/Black wire terminal at neutral relay electrical connector. Scan tester should now display R-D-L. If R-D-L is displayed, go to next step. If R-D-L is not displayed, check for open circuit in White/Black wire between neutral relay and ECM or for defective ECM connector. If wiring and ECM connector are okay, ECM is defective.
  6. Connect test light between White/Black wire terminal on neutral relay electrical connector and ground. Test light should glow when transaxle is in Drive or Reverse. If test light does not glow, go to next step. If test light glows, go to step 10).
  7. Using test light, probe Red/Black wire at park/neutral position switch, located on top of transaxle, near battery. Test light should glow. If test light glows, go to step 9).
  8. If test light does not glow, check for open circuit in Red/Black wire between park/neutral position switch and fuse C-11 (15-amp fuse except GSi) or C-12 (10-amp fuse for Storm GSi), located in junction block behind left kick panel.
  9. Check park/neutral position switch adjustment and check for open circuit in White/Black wire between neutral relay and park/neutral position switch. If wiring and switch adjustment are okay, park/neutral position switch is defective.
  10. Check for defective electrical connection at neutral relay. If electrical connection is okay, check for open circuit in Black ground wire to neutral relay. If wiring is okay, neutral relay is defective.
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