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Transaxle Range Switch: Notes

NOTE: Transaxle range switch is also referred to as Park/Neutral Position (PNP) switch.
  1. Connect scan tool. Turn ignition on, engine off. Using scan tool, observe range switch display while selecting each transaxle range. If each range selection matches scan tool display, see DIAGNOSTIC AIDS . If range selection does not match scan tool display, go to next step.
  2. Using scan tool, observe range switch A/B/C/P display. If HI is indicated for all range signal states, go to step  11. If HI is not indicated for all range states, go to next step.
  3. Turn ignition off. Remove transaxle side cover. See HYDRA-MATIC 4T65-E OVERHAUL article. Disconnect transaxle range switch connector. Turn ignition on, engine off. Using scan tool, observe range switch A/B/C/P display. If HI is indicated for all range signal states, go to next step. If HI is not indicated for all range states, go to step  8.
  4. Using DVOM, measure voltage between ground and terminals "B", "C" and "D" of range switch harness connector, one at a time. See Figure. If voltage is 10-12 volts, go to next step. If voltage is not 10-12 volts, go to step  9.
  5. Connect a fused jumper wire between ground and terminal "D" of range switch connector (signal circuit "A") while monitoring scan tool range switch A/B/C/P parameter. If any other signal circuits display LOW when terminal "A" is grounded, go to step  10. If only signal "A" indicates LOW, go to next step.
  6. Connect fused jumper wire between ground and terminal "B" of range switch connector (signal circuit "B") while monitoring scan tool range switch A/B/C/P parameter. If any other signal circuits display LOW when terminal "B" is grounded, go to step  10. If only signal "B" indicates LOW, go to next step.
  7. Connect fused jumper wire between ground and terminal "C" of range switch connector (signal circuit "C") while monitoring scan tool range switch A/B/C/P parameter. If any other signal circuits display LOW when terminal "C" is grounded, go to step  10. If only signal "C" indicates LOW, go to step  12.
  8. Check for short to ground in range switch signal circuits not indicating HI. Repair as necessary. After repairs, go to step  14. If range switch signal circuits are okay, go to step  13.
  9. Check for open in range switch signal circuits not indicating correct voltage. Repair as necessary. After repairs, go to step  14. If range signal circuits are okay, go to step  13.
  10. Check for shorted together condition in affected range switch signal circuits. Repair as necessary. After repairs, go to step  14. If range switch signal circuits are okay, go to step  13.
  11. Check for open in range switch ground circuit. Repair as necessary. After repairs, go to step  14. If range switch ground circuit is okay, go to next step.
  12. Replace transaxle range switch. See HYDRA-MATIC 4T65-E OVERHAUL article. After repairs, go to step  14.
  13. Replace PCM. After replacement, program PCM. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to next step.
  14. Connect scan tool. Turn ignition on, engine off. Using scan tool, observe range switch display while selecting each transaxle range. If each range selection matches scan tool display, system is okay. If selections do not match scan tool display, repeat test.
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