DTC P0872: Transmission Fluid Pressure Sensor / Switch "C" Circuit Low [11/2021 - ]: Procedure
WARNING: This page is about a different car, the 2024 Lexus IS 500, 2023 Lexus IS 500, and 2022 Lexus IS 500. However, it is still accessible from the selected car via links, so may be relevant.
- READ VALUE USING TECHSTREAM (TPS 1 SWITCH SIGNAL)
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Powertrain / ECT / Active Test / Control the Shift Position / Data List / TPS 1 Switch.
Powertrain > ECT > Active Test
Tester Display Measurement Item Control Range Diagnostic Note Control the Shift Position Operates the shift solenoid valves to allow gears to be selected manually. - Press "→" button: Upshift occurs
- Press "←" button: Downshift occurs
Possible to check operation of the shift solenoid valves.
[Vehicle Condition]
Vehicle speed: 50 km/h (31 mph) or lessPowertrain > ECT > Data List
Tester Display Measurement Item Range Normal Condition Diagnostic Note TPS 1 Switch Oil pressure switch status ON or OFF - ON: Gear is 1st to 5th
- OFF: Gear is 6th to 8th; or shift lever is in P, N or R
- Powertrain > ECT > Active Test
Active Test Display Control the Shift Position Data List Display TPS 1 Switch Result
Result Proceed to When the vehicle is being driven in a gear position between 1st and 5th, ON is displayed for TPS 1 Switch on the Data List. A When the vehicle is being driven in a gear position between 1st and 5th, OFF is displayed for TPS 1 Switch on the Data List. B
Result:
B
See step 3
Result:
A
See step 2
- REPLACE TCM
- Replace the TCM.
Refer to COMPONENTS [11/2021 - ]
Result
Proceed to NEXT
Result:
NEXT
PERFORM A/T CODE REGISTRATION. Refer to REGISTRATION [11/2021 - ]
- Replace the TCM.
- CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - TCM)
- Disconnect the F175 transmission wire connector.
- Disconnect the F156 TCM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition F175-17 (TPS1) - F156-9 (TPS1) Always Below 1 Ω F175-17 (TPS1) or F156-9 (TPS1) - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (TRANSMISSION WIRE - TCM)
Result:
OK
See step 4
- INSPECT TRANSMISSION WIRE (OIL PRESSURE SWITCH)
- Disconnect the oil pressure switch connector.
*a Front view of wire harness connector
(to Oil Pressure Switch Connector)*b Component without harness connected
(Transmission Wire)*c Connector Refer to DISASSEMBLY [11/2021 - ]
- Disconnect the F175 transmission wire connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Oil pressure switch connector - 17 (TPS1) Always Below 1 Ω Oil pressure switch connector or 17 (TPS1) - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE OIL PRESSURE SWITCH. Refer to COMPONENTS [11/2021 - ]
Result:
NG
REPAIR OR REPLACE TRANSMISSION WIRE. Refer to COMPONENTS [11/2021 - ]
- Disconnect the oil pressure switch connector.