DTC P0123: Throttle Position (TP1) Sensor Circuit High Input

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

P0123 - THROTTLE POSITION (TP1) SENSOR CIRCUIT HIGH INPUT

For Vehicles With Electronic Throttle Control (ETC)
Description:	The electronic throttle control (ETC) TP1 sensor was flagged as fault status by the powertrain control module (PCM) indicating a high voltage.
Possible Causes:	ETC TP sensor harness shorted to VREF ETC TP sensor harness shorted to PWR Damaged TP sensor VREF circuit shorted to TP sensor
Diagnostic Aids:	Drive the vehicle, bring it to a stop, and turn the key to the OFF position. Start the vehicle, and run the key on, engine running (KOER) self-test at idle. Access KOER DTCs on the diagnostic tool. The TP1 signal is normally at a high voltage at closed throttle, and a lower voltage at wide open throttle (opposite of TP2).
For All Others
Description:	The TP sensor circuit is monitored by the powertrain control module (PCM) for a high TP rotation angle (or voltage) input through the comprehensive component monitor (CCM). If during the key on engine off (KOEO), or key on, engine running (KOER) the TP rotation angle (or voltage) changes above the maximum calibrated limit, the test fails.
Possible Causes:	TP sensor not seated properly TP circuit short to PWR TP circuit short to VREF SIG RTN circuit open to the TP sensor Damaged TP sensor
Diagnostic Aids:	A TP PID (TP V PID) reading greater than 93% 4.65 volts in KOEO, continuous memory or KOER indicates a hard fault.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
Vehicles With Electronic Throttle Control (ETC)	GO to DV: Throttle Body Assembly ETC STEP DV1.
All others	GO to DH: Throttle Position (TP) Sensor STEP DH8.