P0123

Diagnostic Chart 1 Of 2:

Diagnostic Chart 2 Of 2:

Schematic:

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor contains a potentiometer whose resistance value changes as the throttle valve position changes. The Powertrain Control Module (PCM) provides a 5 volt reference voltage to the TP sensor. The PCM reads the voltage across the TP sensor and converts the voltage into a throttle angle. The TP sensor resistance decreases as the throttle-valve opening increases, and increases as the throttle-valve opening decreases. The TP sensor voltage increases as the throttle-valve opening increases.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ The voltage input is high, and the throttle opening is more than 96 percent.
^ The above condition is present for at least 0.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM records the operating conditions at the time that the diagnostic fails. This information is stored in the Freeze Frame buffer.
^ The PCM enters the Fail-Safe Function and assumes the throttle angle is 20 degrees.

CONDITIONS FOR CLEARING THE DTC
^ The MIL turns OFF after 3 consecutive trips during which the diagnostic runs and does not detect a fault.
^ A History DTC clears after 40 consecutive warm-up cycles without a fault.
^ Use the Clear DTC Information function of the scan tool, or disconnect the PCM battery feed in order to clear the DTC.

DIAGNOSTIC AIDS
Check for any of the following conditions:
^ Check the resistance of the TP sensor. TP sensor resistance between terminals 1 and 2 should be between 2.5k-6.0 K ohms. TP sensor resistance between terminals 1 and 3 should be between 100 ohms and 20 K ohms. Replace the TP sensor if the measured resistance is not within the specified values.
^ Inspect the ground circuit for an open if DTC P0108, P0113, P0118, and P0123 are set together.
^ Look for a faulty electrical connection to the PCM.

An intermittent malfunction may be caused by a fault in the TP sensor electrical circuit. Inspect the wiring harness and the components for any of the following conditions:
^ Backed out terminals
^ Incorrect mating of terminals
^ Broken electrical connector locks
^ Incorrectly formed terminals or damaged terminals
^ Faulty terminal-to-wire connections
^ Physical damage to the wiring harness
^ A broken wire inside the insulation
^ Corrosion of electrical connections, of splices, or of terminals

If DTC P0123 cannot be duplicated, the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

TEST DESCRIPTION
The numbers below refer to the step numbers in the diagnostic table.
1. The Powertrain OBD system check prompts the technician to complete some basic checks, and to save the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data that was taken when the fault occurred. The scan tool saves the information for later reference.
2. Observe the TP sensor parameter from the closed throttle position to the wide open throttle position. The percentage of the TP sensor movement should not be more than 96%.
5. This step checks the reference voltage at the TP sensor.