Code 28, Transmission Range Pressure Switch - Except Lumina: Notes

Transaxle range switch is a multiple signal switch that sends gear selector position information to the PCM. PCM determines gear selection from an internal table. This is important to maintain idle quality when shifting from Park to Drive as well as maintaining correct TCC engagement points. When Code 28 sets, PCM will default to 3rd gear until a correct signal is received by PCM.

NOTE: Test numbers refer to numbers on diagnostic chart.

Checks for proper operation of transmission range switch.
Checks for an open, grounded or shorted to voltage circuit.