Circuit Description
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 engine control module (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 TP sensor 1 signal increases from 0.4-4.35 volts, while the voltage on the TP sensor 2 signal decreases from 4.55- 0.60 volts. DTC P0222 sets when TP sensor 2 signal voltage at the ECM is below the calibrated voltage value.
Conditions for Setting the DTC
DTC P0222 will set if TP sensor 2 signal voltage is less than 0.16 volts when:
| • | The condition exists for longer than 140 ms. |
| • | The battery voltage is greater than 7 volts. |
DTC P0222 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 P0222 is a type A DTC for 2002, and a type B DTC for 2003.
Diagnostic Aids
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 the area where an open or a short to ground in the wiring may exist.
An intermittent open in TP sensor 2 can set this DTC. Monitor the voltage range of the sensor using THROTTLE ACTUATOR CONTROL in the SPECIAL FUNCTIONS section of the scan tool, which will command the throttle actuator control module to move the throttle plate.
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.
