Diagnostic Aids

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: The TAC motor is extremely strong. Never use your fingers to move the throttle plate unless the TAC module connector is disconnected.

If a low or high voltage TP sensor 1 or 2 DTC is also set, diagnose that DTC first.

If DTC P0121 is also set, without P0221, TP sensor 1 circuit is most likely out of range. If DTC P0221 is also set without P0121, TP sensor 2 circuit is most likely out of range. If both P0121 and P0221 are also set, corrosion or high resistance may exist in the 5-volt reference "B" circuit or reference return circuit. Check for corrosion and loose or spread terminals.

A skewed TP sensor 1 or 2 can set this DTC. Remove the air induction tubing then wait at least 1 minute with the ignition on. Using scan tool, monitor the voltage range of the sensor by slowly moving the throttle plate with a flat screwdriver from the full closed to the full open position. For approximate TP sensor 1 vs. TP sensor 2 voltages, see THROTTLE ANGLE POSITION VS VOLTAGE table under DTC P0221: TP SENSOR NO. 2 CIRCUIT PERFORMANCE.