P0122

Diagnostic Chart:

Schematic:

The throttle actuator control (TAC) module contains two throttle position (TP) sensors with a common 5 volt supply, a common ground, and two 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% throttle to wide open throttle, the voltage on the TP sensor 1 signal increases from 0.50 volts to 4.25 (+/-0.1) volts, while the voltage on the TP sensor 2 signal decreases from 4.45 volts to 0.70 (+/-0.1) volts. DTC P0122 sets when TP sensor 1 signal voltage at the ECM is below the calibrated voltage value.

DTC PARAMETERS
DTC P0122 will set if TP sensor 1 signal voltage is less than 0.18 volts when:
^ Condition exists for longer than 140 ms
^ Main relay voltage greater than 8.0 volts
^ Ignition is On

DTC P0122 diagnostic runs continuously with ignition On.

P0122 is a type B DTC.

DIAGNOSTIC AIDS
To locate an intermittent problem, use Scan tool to monitor TP SENSOR 1 voltage with ignition On, engine Off. Wiggling wires while watching for a change in TP SENSOR 1 voltage may locate the area where an open in the 5 volt reference or a short to ground in the wiring may exist.

Circuit 2701 (TO sensor 1/TP sensor 2) and circuit 1274 (APP sensor 2) share the same 5 volt reference supply (5 volt Ref-B).

NOTE: TP ANGLE on Scan tool is based off of TP sensor 1 only.