P0221

DTC P0221: Throttle Position (TP) Sensor 2 Performance

Wiring Diagram:

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 plate 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 increases from below 1 V at idle to above 4 V at Wide Open Throttle (WOT). TP sensor 2 signal voltage decreases from above 4 V at idle to below 1 V at WOT.

Conditions for Setting the DTC
- Ignition ON.
- Difference between TP1 value and TP2 value is greater than 6.003 TPS.
- Actual TP value is less than 90.002 TPS.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn OFF at the end of a consecutive validation cycle in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
If the DTC P0221 cannot be duplicated, the information included in the Freeze Frame data can be useful. Use the scan tool DTC information data to determine the status of the DTC.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that a condition exists. If there is a condition with a TP sensor circuit, the scan tool displays, Disagree.
5. This step tests for high resistance in the 5 volt reference circuit of the TP sensors. If the DMM does not display more than the specified voltage there is high resistance in the circuit.
8. This step tests for high resistance in the low reference circuit of the TP sensor. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

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DTC Troubleshooting