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P0123

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with three circuits, a 5-volt reference, a low reference and a signal. The PCM provides the TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor from the closed throttle position to the Wide Open Throttle (WOT) position provides the PCM with a signal voltage from less than 1.0 volt to greater than 4.0 volts through the TP sensor signal circuit. If the PCM detects an excessively high signal voltage, this DTC will set.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ TP sensor signal voltage is more than 4.9 volts.
^ The above conditions are present for longer than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ First failure:
- The MIL is not turned ON.
- A DTC is stored in memory under Failed Last Test.
- The Failure Records are stored.
^ Second consecutive drive cycle with a failure:
- The MIL is turned ON.
- A DTC is stored in memory under history.
- The Freeze Frame data is stored.
- The Failure Records are stored.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after the third consecutive trip the diagnostic has run and passed.
^ The history DTC will clear if the fault conditions have not been detected for 40 warm-up cycles.
^ A scan tool can be used to clear DTC information.

TEST DESCRIPTION

Steps 1-5:




Steps 6-19:




The number below refers to the step number on the diagnostic table.
10. An internally shorted EGR valve could cause a high voltage condition on the 5-volt reference circuit.