P0122

DTC P0122

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 less than 0.98 volts, DTC P0122 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

CONDITIONS FOR RUNNING THE DTC
- The battery voltage is more than 10 volts.
- The ignition is ON.
- DTC P0122 runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The TP sensor 1 voltage is less than 0.98 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 DESCRIPTION

Step 1 - Step 8:

Step 9 - Step 17:

The numbers below refer to the step numbers on the diagnostic table.
4. The ECM performs a comparison of the signals from both TP sensors during the entire range of operation. If the DTC does not set with the key ON and the accelerator pedal released, actuating the throttle may cause the DTC to set.
7. The 5-Volt reference for the TP sensors and the APP sensor 2 are connected inside the ECM. This step is to determine if the APP sensor is affecting the 5-Volt reference circuit of the TP sensors.