P0122: OBD-II code P0122 means the throttle position sensor A is reporting a signal lower than possible — typically a shorted signal wire or a bad sensor.

Symptoms

• Check engine light is on, often with reduced-power mode active and a warning message on the dashboard.
• Poor throttle response, hesitation, and inconsistent idle because the PCM can't trust the pedal input.
• The vehicle may refuse to rev beyond a limp-mode limit, or stall on light throttle inputs.

Common causes

• A failed TPS or accelerator pedal position (APP) sensor with a shorted or dead signal element.
• A shorted-to-ground signal wire between the sensor and the PCM.
• A corroded or damaged connector at the TPS/APP sensor causing an intermittent low reading.

What to do?

Read live TPS voltage in scan data — it should start near 0.5 V at rest and rise to about 4.5 V at full throttle. Backprobe with a DMM if the scan tool disagrees. Replace the sensor if it reads stuck low. Perform a throttle relearn with a scan tool after any sensor replacement.