P0122

DTC P0122

CIRCUIT DESCRIPTION
The throttle position (TP) sensor is used by the engine control module (ECM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits:
- A 5-volt reference circuit
- A low reference circuit
- A TP sensor signal circuit

The ECM provides the TP sensor with 5 volts on the 5-volt reference circuit, and a ground on the low reference circuit. The TP sensor provides a signal voltage that changes relative to throttle plate angle. The TP sensor signal voltage at idle is less than 0.5 volt. The TP sensor voltage is typically near 0.0 volts at idle, but could be as high as 0.5 volts. The TP sensor voltage should increase to above 4 volts at wide open throttle (WOT). If the ECM detects an excessively low signal voltage, 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 ignition is ON or the engine is running.
- DTC P0122 runs continuously once the above condition is met.

CONDITIONS FOR SETTING THE DTC

IMPORTANT: The scan tool displays a voltage near 0.0 volts. Do not use the scan tool voltage parameter to determine if there is a TP sensor condition.

The ECM detects that the TP sensor signal voltage is less than 0.14 volt for a total of 2.5 seconds during a 5 second period.

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/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.

TEST DESCRIPTION

Steps 1-3:

Steps 4-6:

Steps 7-8:

Steps 9-13:

Steps 14-15:

The numbers below refer to the step numbers on the diagnostic table.
3. If the DTC P0122 cannot be duplicated, the information included in the Freeze Frame data can be useful. Use the scan tool information to determine the status of the DTC. If the DTC occurs intermittently, using intermittent conditions may isolate the condition.
4. This step determines if there is a short to ground or an open condition in the circuits.