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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 73 (Automatic Transmission Diagnosis - 4L80-E (Gasoline)) >> Diagnostic Tests >> DTC P0706: Transmission Range Switch Circuit - Low Input >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 GMC Cab & Chassis Sierra and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the diagnostic system check? If so, go to next step. If not, see DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Install a scan tool. Turn ignition on, engine off. Select TR SW. on the scan tool. With the scan tool, observe the TR SW. display while selecting each transmission range. Does each selected transmission range match the scan tool TR SW. display? If so, see DIAGNOSTIC AIDS  . If not, go to next step.
  3. Inspect the PNP switch assembly for the following:
    • Damage
    • Loose Or Missing Mounting Hardware
    • Proper Adjustment

    See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Inspect the shift cable for damaged or stretched cable. Did you find and correct a condition? If so, go to step  16 . If not, go to next step.

  4. With the scan tool, observe the TR SW. A/B/C/P display. Does the scan tool TR SW. A/B/C/P parameter indicate "HI" for all range signal states? If so, go to step  13 . If not, go to next step.
  5. Turn ignition off. Disconnect the TR switch 4-way connector. Turn ignition on, engine off. Does the scan tool TR SW. A/B/C/P parameter indicate "HI" for all range signal states? If so, go to next step. If not, go to step  10 .
  6. Using a DVOM and the Connector Test Adapter Kit (J-35616-A), measure the voltage from TR switch 4-way connector terminal "A" to ground. Measure the voltage from TR switch 4-way connector terminal to ground. Measure the voltage from TR switch 4-way connector terminal "C" to ground. Measure the voltage from TR switch 4-way connector terminal "D" to ground. Does the voltage measure 10-12 volts at all 4 terminals? If so, go to next step. If not, go to step  11 .
  7. Connect a fused jumper wire from TR switch 4-way connector terminal "D" (signal "A" circuit) to ground while monitoring the scan tool TR SW. A/B/C/P parameter. When the signal "A" circuit (771) is grounded, do any other signal circuits indicate "LOW"? If so, go to step  12 . If not, go to next step.
  8. Connect a fused jumper wire from TR switch 4-way connector terminal "B" (signal "B" circuit) to ground while monitoring the scan tool TR SW. A/B/C/P parameter. When the signal "B" circuit (772) is grounded, do any other signal circuits indicate "LOW"? If so, go to step  12 . If not, go to next step.
  9. Connect a fused jumper wire from TR switch 4-way connector terminal "C" (signal "C" circuit) to ground while monitoring the scan tool TR SW. A/B/C/P parameter. When the signal "C" circuit (773) is grounded, do any other signal circuits indicate "LOW"? If so, go to step  12 . If not, go to step  14 .
  10. Test the TR switch signal circuits (771, 772, 773 and 776) that did not indicate "HI" for a short to ground. Did you find and correct the condition? If so, go to step  16 . If not, go to step  15 .
  11. Test the TR switch signal circuits (771, 772, 773 and 776) that did not indicate proper voltage for an open. Did you find and correct the condition? If so, go to step  16 . If not, go to step  15 .
  12. Test the affected TR switch signal circuits for a shorted together condition. Did you find and correct the condition? If so, go to step  16 . If not, go to step  15 .
  13. Test the TR switch ground circuit (451) for an open. Did you find and correct the condition? If so, go to step  16 . If not, go to next step.
    14. NOTE: The TR switch is part of the Park/Neutral Position (PNP) switch.
  14. Replace the TR switch. See PARK/NEUTRAL POSITION SWITCH  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step  16 .
  15. Replace the PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to next step.
  16. Perform the following procedures to verify the repair:
    • Select DTC.
    • Select CLEAR INFO.
    • Drive the vehicle greater than 5 MPH for a short distance, then stop the vehicle.
    • Select each transmission range.
    • Place the gearshift lever in Park.
    • Select SPECIFIC DTC.
    • Enter DTC P0706.

    Has the test run and passed? If so, system is okay. If not, go to step  1 .

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