The throttle actuator control (TAC) module contains 2 throttle position (TP) sensors with a common 5-volt supply, a common ground, and 2 independent signal circuits that vary resistance according to changes in throttle plate position. The ECM measures the signal voltage from each TP sensor, which is a reduced value of the ECM 5-volt reference. As the throttle plate opens from 0 percent throttle to wide open throttle (WOT), the voltage on the TP sensor 1 signal increases from 0.40-4.35 volts, while the voltage on the TP sensor 2 signal decreases from 4.55-0.60 volts. DTC P0223 sets when the TP sensor 2 signal voltage at the ECM is above the calibrated voltage value.

DTC P0223 will set if TP sensor 2 signal voltage is greater than 4.80 volts when:

DTC P0223 diagnostic runs continuously with engine running.

Important: The MIL will only illuminate if the fault is present for longer than 5 seconds for 2002 only.

DTC P0223 is a type A DTC for 2002, and a type B DTC for 2003.

To locate an intermittent problem, use the scan tool to monitor TP SENSOR 2 voltage with the ignition ON and the engine OFF. Wiggling the wires while watching for a change in TP SENSOR 2 voltage may locate an area where an open in the ground circuit or a short to voltage in the wiring may exist.

If a TP sensor 1 signal circuit fault is detected, the ECM will default to REDUCED POWER mode if vehicle speed is below 56 km/h (35 mph) with the APP angle at 0 percent. Otherwise, when the circuit fault occurs, TP sensor 2 will be used and vehicle performance will not be affected.

Important: The ECM will remain in these conditions for the entire ignition cycle even if the fault is corrected.

Circuit 486 (TP sensor 1/TP sensor 2) and circuit 1274 (APP sensor 2) share the same 5-volt reference supply, 5-volt Ref-B.

Important: TP ANGLE on the scan tool is based off of TP sensor 1 only.

The CMP/ECT/IAT/EGR/MAF/MAP/TP1/TP2 sensors share the same sensor return circuit 652.