P0123

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor is used by the PCM in order to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits: a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides the TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor 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 more 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
^ The TP sensor signal voltage is more than 4.9 volts.
^ The above conditions are present for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ The History DTC clears after 40 consecutive warm-up cycles occur without a malfunction.
^ The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-7:

Steps 8-19:

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.