P0123

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematics:

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor is a potentiometer. The control module supplies the TP sensor a reference voltage, a signal, and ground circuits. When the throttle is depressed, the TP sensor signal rises to near the reference voltage. When the throttle is released, the TP sensor signal decreases from the reference voltage. The control module monitors the TP sensor signal circuit voltage in order to determine the throttle blade angle, or opening.

This DTC is designed to detect a TP sensor signal voltage higher than the possible operating range of a normally functioning TP sensor.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The TP sensor signal voltage is more than 4.7 volts for 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
^ The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tools Freeze Frame and Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
^ A scan tool can clear the DTCs.

DIAGNOSTIC AIDS
^ The scan tool reads the throttle position in volts. The scan tool should read about 0.45-0.85 volt with the the ignition switch turned ON and the throttle closed or at idle. The voltage should increase at a steady rate as the throttle is moved toward the Wide Open Throttle (WOT) position.
^ The scan tool will read the throttle angle percentage as 0 percent at closed throttle and 100 percent at WOT.
^ Scan the TP sensor while depressing the accelerator pedal with the engine turned OFF and the ignition turned ON. The display should vary from less than 1.25 volts when the throttle is closed to more than 4.5 volts when the throttle is held in the WOT position.
^ This DTC will result if the TP ground circuit is open or if the TP signal circuit is shorted to the voltage.
^ For other intermittents refer to Symptoms. Symptom Related Diagnostic Procedures

An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Diagrams.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Diagrams.

TEST DESCRIPTION
The numbers below refer to the step numbers in the diagnostic table.
2. If the TP signal measures more than 4.8 volts, the conditions exists.
3. If the VCM and the wiring are okay, the TP signal should decrease to less than 0.25 volt with the TP sensor disconnected. This test could set DTC P0122.