P0123
DTC P0123
CIRCUIT DESCRIPTION
The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-Volt reference circuit and a common low reference circuit. The 5-Volt reference circuit is also shared with accelerator pedal position (APP) sensor 2. The 5-Volt reference voltage is supplied on 2 separate engine control module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to throttle the plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the 5-Volt reference and decreases as the throttle plate is opened. If the ECM detects the TP sensor 1 signal voltage is more than 4.89 volts, DTC P0123 sets.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0123 Throttle Position (TP) Sensor 1 Circuit High Voltage
CONDITIONS FOR RUNNING THE DTC
- The battery voltage is more than 10 volts.
- The ignition is ON.
- DTC P0123 runs continuously once the above conditions are met.
CONDITIONS FOR SETTING THE DTC
The TP sensor 1 voltage is more than 4.89 volts for more than 60 milliseconds.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
- The control module commands the TAC system to operate in the Reduced Engine Power mode.
- A message center or an indicator displays Reduced Engine Power.
- Under certain conditions the control module commands the engine OFF.
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.
TEST
