Chart C-1A, Park/Neutral Switch 1.6L TBI T Body

Fig 1: Chart C-1A, Park/Neutral Switch Diagram (1.6L TBI T Body)

Courtesy of GENERAL MOTORS CORP.

Park/Neutral switch contacts are a part of neutral safety switch and are closed to ground in park or neutral, and open in drive ranges. ECM supplies ignition voltage through a current limiting resistor to signal wire and senses a closed switch when voltage on signal wire drops to less than one volt. ECM uses P/N signal as one of the inputs to control idle air and spark timing.

1. This test checks for a closed switch to ground in park position. Different scan tools will read P/N differently. Check tester operators 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 range.

Fig 2: Chart C-1A, Troubleshooting Diagram (1.6L TBI T Body)

Courtesy of GENERAL MOTORS CORP.