2005 Ford Econoline E150, Van Cargo, 5.4 LFACTORY OEM SERVICE PROCEDURE

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

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.
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