P0992-2/4/OD HYDRAULIC PRESSURE TESTFor a complete wiring diagram Refer to Section 8W.Theory of OperationPressure switches are normally off or open (no pressure applied) and read high (+12 volts). When an element is applied, the corresponding pressure switch closes to ground (0 volts) or turns
on. The controller tests the OD and 2/4 pressure switches when they are off (when the corresponding friction element is not applied) by briefly applying the OD and 2/4 elements which will cause the corresponding
pressure switch to close. The test verifies that the switches are operational and that the switch will close when the corresponding element is applied. If a switch fails to respond, it is re-tested. The
MIL illuminates and the transmission system defaults to limp-in mode. - When Monitored:In any forward gear with engine speed above 1000 rpm, shortly after a shift and every minute thereafter.
- Set Condition:After a shift into a forward gear, with engine speed greater than 1000 rpm, the PCM momentarily turns on element pressure to the clutch circuits that do not have pressure to identify that
the correct pressure switch closes. If the pressure switch does not close 2 times the DTC sets.
Possible Causes
CONDITION P0992 PRESENT
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 42RLE - DIAGNOSIS AND TESTING).1. CHECK TO SEE IF DTC P0992 IS CURRENTThe vehicle must be driven to set this DTC. The transmission must be at operating temperature with the Engine rpm above 1000 rpm.This DTC is an indication of both the 2/4 and the O/D Hydraulic Pressure Switch DTCs being present.Perform the diagnostic procedures for both P0845 and P0870.With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.If there are no possible causes remaining, view repair.Repair- Refer to the Transmission category and perform the diagnostic procedures for P0845 and P0870.