P0122

CIRCUIT DESCRIPTION
The throttle position (TP) sensor is a potentiometer. The powertrain control module (PCM) supplies the TP sensor a reference voltage, a signal, and low reference 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 diagnostic trouble code (DTC) is designed to detect a TP sensor signal voltage lower 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 less than 0.25 volts for 1 second or more.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
The scan tool reads throttle position in volts. The TP should read about 0.45-0.85 volts with the throttle closed and the ignition ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward wide open throttle (WOT). The scan tool will also read the throttle angle percentage. 0 percent at closed throttle. 100 percent at WOT.

An open or short to ground in the 5-volt reference circuit or the TP sensor signal circuit results in a DTC P0122. Refer to Symptoms - Computers and Controls Systems. Symptom Related Diagnostic Procedures

Scan the TP sensor signal while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from below 1.25 volts (1,250 mV) with the throttle closed, to more than 4.5 volts (4,500 mV) when the throttle is held at the WOT position.

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 Diagnostic Aids.

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

TEST DESCRIPTION

Steps 1-9:

Steps 10-15:

The number below refer to the step number on the diagnostic table.
8. Malfunctioning components that share the TP sensor 5-volt reference circuit could cause a low voltage condition on this circuit.