P0122

DTC P0122

CIRCUIT DESCRIPTION
The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from above 4 volts at idle to below 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from below 1 volt at idle to above 4 volts at WOT.

If the ECM detects TP sensor 1 signal voltage is too low, this DTC sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0122 Throttle Position (TP) Sensor 1 Circuit Low Voltage

CONDITIONS FOR RUNNING THE DTC
- DTCs P0601, P0602, P0603, P0604, P0606, P0607, P0641, P0651 are not set.
- The ignition is ON, with the engine OFF, or the engine is operating.
- The ignition 1 voltage is more than 5.23 volts.
- DTC P0122 runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ECM detects the TP sensor 1 signal voltage is less than 0.275 volts for less than 1 second.

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.

DIAGNOSTIC AIDS
- Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
- If there is a condition with the TP sensors the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.
- For an intermittent condition, refer to Intermittent Conditions. Diagnostic Strategies

TEST DESCRIPTION

Steps 1 - 6:

Steps 7 - 14:

The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that a condition exists.
4. The TP sensors share a 5-volt reference circuit. If both DTCs P0122 and P0222 set, test for a condition in the 5-volt reference circuit.
5. The ECM produces a measurable steady-state amperage that provides the 5 volt reference to the TP sensors. If the amperage on the 5-volt reference circuit is less than 50 mA, test the 5-volt reference circuit for an open or a high resistance.
6. This step tests the signal 1 circuit of the TP sensor. If the TP sensor 1 voltage parameter is not 4.8-5.2 volts, test for a condition in the signal 1 circuit.