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Test AJ: Transmission Range Indicator (PRND321) Inoperative Or Displays Incorrect Range

  1. Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel, to right of steering column. See Figure . Turn ignition switch to RUN position. Using scan tool, select TRS SW and observe TR SW display while selecting each transmission range (gear). If selected range does not match scan tool display, go to next step. If selected range matches scan tool display, go to DIAGNOSING INTERMITTENTS  .
  2. Using scan tool, observe TR SW A/B/C/P display. If scan tool does not display HI for all range signal states, go to next step. If scan tool displays HI for all range signal states, go to step  12 .
    3. NOTE: Transmission Range Switch (TRS) may also be referred to as Park/Neutral Position (PNP) switch or neutral safety switch.
  3. Check transmission linkage and TRS adjustment. See ADJUSTMENTS in appropriate AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION SERVICING. If no adjustment is required, go to next step. If adjustment is required, adjust as necessary. After repair, go to step  15 .
  4. Turn ignition switch to OFF position. Disconnect TRS 4-pin harness connector C2. TRS is located left of engine, on transaxle. Turn ignition switch to RUN position. Using scan tool, observe TR SW A/B/C/P parameter. If scan tool displays HI for all TRS signal circuits, go to next step. If scan tool does not display HI for all TRS signal circuits, go to step 9 .
  5. Using a Digital Volt-Ohmmeter (DVOM), measure voltage between ground and in turn, TRS harness connector C2 terminals "A" (White wire), "B" (Yellow wire), "C" (Gray wire) and "D" (Black/White wire). See Fig 1 . If voltage is 10-12 volts for all measurements, go to next step. If voltage is not 10-12 volts for all measurements, go to step  10 .
    Fig 1: Identifying Transmission Range Switch Harness Connector C2 Terminals
    G00032227Courtesy of GENERAL MOTORS CORP.
  6. Connect a fused jumper wire between ground and TRS signal circuit "A" at TRS harness connector terminal "D" (Black/White wire) while monitoring scan tool TR SW A/B/C/P parameter. If only signal "A" displays LOW when terminal "D" is grounded, go to next step. If any other signal circuits display LOW when terminal "D" is grounded, go to step  11 .
  7. Connect a fused jumper wire between ground and TRS signal circuit "B" at TRS harness connector terminal "B" (Yellow wire) while monitoring scan tool TR SW A/B/C/P parameter. If only signal "B" displays LOW when terminal "B" is grounded, go to next step. If any other signal circuits display LOW when terminal "B" is grounded, go to step  11 .
  8. Connect a fused jumper wire between ground and TRS signal circuit "C" at TRS harness connector terminal "C" (Gray wire) while monitoring scan tool TR SW A/B/C/P parameter. If any other signal circuits display LOW when terminal "C" is grounded, go to step  11 . If only signal "C" displays LOW when terminal "C" is grounded, go to step  13 .
  9. Test between Powertrain Control Module (PCM) and TRS harness connectors for open in TRS signal circuit(s) not displaying HI. See TRANSMISSION RANGE SWITCH SIGNAL CIRCUIT IDENTIFICATION  table. See Figure and Fig 1 . PCM is located in front left corner of engine compartment, inside air cleaner. If an open is not found, go to step  14 . If an open is found, repair as necessary. After repair, go to step  15 .
    TRANSMISSION RANGE SWITCH SIGNAL CIRCUIT IDENTIFICATION

    PCM Terminal No. (Connector) TRS Terminal Wire Color TRS Signal Circuit
    16 (C2) "A" White "P"
    68 (C1) "B" Yellow "B"
    56 (C2) "C" Gray "C"
    18 (C2) "D" Black/White "A"
  10. Test between Powertrain Control Module (PCM) and TRS harness connectors for open in TRS signal circuit(s) not measuring 10-12 volts. See TRANSMISSION RANGE SWITCH SIGNAL CIRCUIT IDENTIFICATION  table. See Figure and Fig 1 . If an open is not found, go to step  14 . If an open is found, repair as necessary. After repair, go to step  15 .
  11. Test between Powertrain Control Module (PCM) and TRS harness connectors for TRS signal circuits shorted to each other. See TRANSMISSION RANGE SWITCH SIGNAL CIRCUIT IDENTIFICATION  table. See Figure and Fig 1 . If a short is not found, go to step  14 . If a short is found, repair as necessary. After repair, go to step  15 .
  12. Test Black wire between TRS harness connector terminal "D" and ground point G113 for an open. Ground point G113 is located in lower left front of engine, on transaxle stud, to left of starter. If an open is not found, go to next step. If an open is found, repair as necessary. After repair, go to step  15 .
  13. Replace TRS. See appropriate AUTOMATIC TRANSMISSIONS article in TRANSMISSION SERVICE & REPAIR. After repair, go to step  15 .
  14. Replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, go to next step.
  15. Turn ignition switch to RUN position. Using scan tool, select TRS SW and observe TR SW display while selecting each transmission range (gear). If selected range does not match scan tool display, go to step  2 . If selected range matches scan tool display, system is okay.
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