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P0871-OD PRESSURE SWITCH RATIONALITY (CONTINUED) Theory of Operation The Transmission system uses five pressure switches to monitor the fluid pressure in the LR, 2C, 4C, UD, and OD GEAR L/R 2C 4C UD OD REVERSE OPEN OPEN OPEN OPEN OPEN P/N CLOSED** OPEN OPEN OPEN OPEN 1ST CLOSED* OPEN OPEN CLOSED OPEN 2ND OPEN CLOSED OPEN CLOSED OPEN 2ND PRIME OPEN OPEN CLOSED CLOSED OPEN 3RD OPEN OPEN OPEN CLOSED CLOSED 4TH OPEN OPEN CLOSED OPEN CLOSED 5TH OPEN CLOSED OPEN OPEN CLOSED *L/R is closed if output speed is below 100 rpm in Drive and Manual 2. L/R is closed in Manual 1. **May be open when rolling in Neutral or at low oil temperatures. Diagnostic Test 1. DETERMINING IF RELATED RELAY DTC’S ARE PRESENT With the scan tool, check for other transmission DTC’s. Are there any Transmission Control Relay related DTC’s present? Yes >> Refer to the Transmission category and perform the appropriate symptom. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. No >> Go To 2 2. LINE PRESSURE DTCS PRESENT With the scan tool, read Transmission DTCs. Are there any Line Pressure DTCs present? Yes >> Refer to the Transmission category and perform the appropriate symptom. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. No >> Go To 3 3. CHECK FOR OTHER PRESSURE SWITCH DTCS With the scan tool, check Transmission DTCs. Are there two or more other pressure switch rationality DTCs present in addition to P0871? Yes >> Go To 5 No >> Go To 4 21 - 170 AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS WK |