Code P0123, TP Sensor Signal High: Notes

Throttle Position (TP) sensor provides a voltage signal that changes relative to throttle blade angle. Signal voltage will vary from .20-.74 volt or at idle to approximately 5 volts at Wide Open Throttle (WOT). TP sensor signal is one of the most important inputs used by control module for fuel control and for most other control module control outputs. On non-adjustable TPS sensors, each time voltage drops below 1.25 volts and stops, control module assumes this value as 0 throttle angle and measures percent throttle from this point on.

1. With closed throttle, ignition on, or at idle, voltage at control module TP sensor signal circuit should be .20-.74 volt.
2. With TP sensor disconnected, TP sensor voltage should decrease and Code P0122 will set. This test verifies that control module and wiring are okay.
3. Probing ground circuit with a test light check sensor ground circuit. A faulty sensor ground circuit will cause Code P0123 to set.