Transmission Position Sensor/Switch: Testing and Inspection

1988 Chevrolet Monte Carlo V6-262 4.3LSECTION Testing and Inspection

Fig. 001 Chart C-1A-1 Park/Nuetral Switch Diagnosis:





Fig. 009 - Wiring Diagram for Chart C-1A Park/Neutral Switch. VIN Z:





CHART C-1A

PARK/NEUTRAL SWITCH DIAGNOSIS

5.0L "F" SERIES

4.3L "B & G" SERIES

FUEL INJECTION (TBI)

Circuit Description: The Park/Neutral switch contacts are a part of the Neutral Start switch and are closed to ground in park or neutral, and open in drive ranges.
The ECM supplies ignition voltage through a current limiting resistor to CKT 434 and senses a closed switch, when the voltage on CKT 434 drops to less than one volt.
The ECM uses the P/N signal as one of the inputs to control:
Idle Air Control
VSS Diagnostics



Test Description: Numbers below refer to circled numbers on Diagnostic Chart
1. Checks for a closed switch to ground in park position. Different makes of "Scan" tools will read P/N differently. Refer to tool operations manual for type of display used.
2. Checks for an open switch in drive range.
3. Be sure "Scan" indicates drive, even while wiggling shifter to test for an intermittent or misadjusted switch in drive range.






RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.