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Home >> GMC >> 1992 >> Forward Control 5.7 K, Standard >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Diagnosis - A/T >> Diagnostic Flow Charts (Cars) >> Chart C-1A, Park/Neutral Switch 2.2L, 2.3L, 3.1L, 3.4L, 5.0L & 5.7L PFI 4.3L, 5.0L & 5.7L TBI A, B, F, J, L, N, W & Y Bodies

Chart C-1A, Park/Neutral Switch 2.2L, 2.3L, 3.1L, 3.4L, 5.0L & 5.7L PFI 4.3L, 5.0L & 5.7L TBI A, B, F, J, L, N, W & Y Bodies

Fig 1: Chart C-1A, Park/Neutral Switch Diagram (A & L Bodies PFI)
G92C13740Courtesy of GENERAL MOTORS CORP.
Fig 2: Chart C-1A, Park/Neutral Switch Diagram (1991 - 4.3L, 5.0L & 5.7L TBI B Body)
G92D13741Courtesy of GENERAL MOTORS CORP.
Fig 3: Chart C-1A, Park/Neutral Switch Diagram (1992 - 5.0L & 5.7L TBI B Body)
G92E13742Courtesy of GENERAL MOTORS CORP.
Fig 4: Chart C-1A, Park/Neutral Switch Diagram (3.1L, 5.0L & 5.7L PFI F & Y Bodies)
G92F13743Courtesy of GENERAL MOTORS CORP.
Fig 5: Chart C-1A, Park/Neutral Switch Diagram (5.0L F Body TBI)
G92G13744Courtesy of GENERAL MOTORS CORP.
Fig 6: Chart C-1A, Park/Neutral Switch Diagram (2.2L J Body PFI)
G92H13737Courtesy of GENERAL MOTORS CORP.
Fig 7: Chart C-1A, Park/Neutral Switch Diagram (2.3L & 3.1L N & J Bodies PFI)
G92H13745Courtesy of GENERAL MOTORS CORP.
Fig 8: Chart C-1A, Park/Neutral Switch Diagram (3.1L & 3.4L W Bodies)
G92I13746Courtesy of GENERAL MOTORS CORP.

ECM supplies ignition voltage through a current limiting resistor to circuit No. 434 and senses a closed switch when voltage on circuit No. 434 drops to less than one volt. ECM uses Park/Neutral signal as one of the inputs to control Idle Air Control (IAC), Vehicle Speed Sensor (VSS) and Exhaust Gas Recirculation (EGR).

If circuit No. 434 indicates while in drive range, EGR would be inoperative, resulting in possible detonation. If circuit No. 434 indicates open, a drop in idle may occur when gear selector is moved into drive range.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. This test checks for a closed switch to ground in park position. Different makes of scan tools will read Park/Neutral differently. Check scan tool operator's manual for type of display used.
  2. This test checks for an open switch in drive range.
  3. Ensure scan tool indicates drive, even while wiggling shifter to test for an intermittent or misadjusted switch in drive or overdrive range.
Fig 9: Chart C-1A, Troubleshooting Diagram (A, B, F, J, L, N, W & Y Bodies)
G92J13739Courtesy of GENERAL MOTORS CORP.
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