Home/Lexus/LS/Lexus LS II (1994-2000)/Repair manual/Testing & Diagnostics/DTC P1400: SUB-THROTTLE POSITION (SUB-TP) SENSOR MALFUNCTION

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DTC P1400: SUB-THROTTLE POSITION (SUB-TP) SENSOR MALFUNCTION Lexus LS II

Testing & Diagnostics

CAUTION

If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction.

Circuit Description

The SUB-TP sensor is similar to the main TP sensor. SUB-TP sensor is used for Traction Control System (TRAC). DTC is set when ECM consistently detects less than .1 volt on VTA2 circuit and closed SUB-TP switch is off. DTC will also set if ECM detects more than 4.9 volts on circuit VTA2. Possible causes are

Open or short in SUB-TP sensor circuit.
SUB-TP sensor.
ECM.