Transmission Position Sensor/Switch: Testing and Inspection

Fig. 004 Wiring Diagram for Chart C-1A-2:

Fig. 1 Chart C-1A-2 PARK NEUTRAL SWITCH DIAGNOSIS:

CHART C-1A-2

PARK/NEUTRAL SWITCH DIAGNOSIS

2.0L (VIN 1) "J" 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
If CKT 434 indicates drive (open), a dip in the idle may exist when the gear selector is moved into drive range.



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.