Code P1401: Sub-Throttle Position (Sub-TP) Sensor Circuit Range/Performance Problem: Notes
WARNING: This page is about a different car, the 1995 Lexus LS 400. However, it is still accessible from the selected car via links, so may be relevant.
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.