P1122

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 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 Diagnostic Trouble Code (DTC) is designed to detect intermittent low signal voltage on the TP sensor signal circuit.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The TP sensor voltage is less than 0.25 volts for less than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The control module stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
^ 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 non-emission related diagnostic.
^ Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
The scan tool reads throttle position in volts. The TP should read between 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 the Wide Open Throttle (WOT) position.

Also, some scan tools will read the throttle angle. 0 percent equals closed throttle and 100 percent equals WOT.

An intermittent open or short to ground in the 5-volt reference circuit or the TP sensor signal circuit could result in a DTC P1122. If a low voltage reading is present, additional sensor circuit voltage codes could be set. Refer to any non-intermittent DTCs that are set.

Observe the TP sensor while depressing the accelerator pedal with the ignition turned ON, leaving the engine OFF. The display should vary from about 0.5 volts (500 mV) with the throttle closed, to more than 4.5 volts (4,500 mV) when throttle is held at the Wide Open Throttle (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 Diagrams.

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

TEST DESCRIPTION

Steps 1-8:

The number below refers to the step number on the diagnostic table.
2. If the TP sensor voltage is less than 0.25 volts, then the condition is present. Even though DTC P0122 did not set, this DTC is more comprehensive and may aid in diagnosis.