P2112 indicates the engine control module (PCM/ECM) has detected that the electronic throttle body is stuck in or near the closed position when a more open position is being commanded. The throttle actuator motor cannot move the throttle plate as requested, which typically forces the vehicle into a reduced-power (limp) mode. This code only applies to drive-by-wire throttle systems.
A mechanical fault inside the throttle body is the most common cause. Carbon deposits on the throttle plate and bore, a worn actuator motor, or a damaged gear/spring can physically prevent the plate from opening even when the PCM commands it to.
Corroded, chafed, loose, or water-damaged connectors and wiring between the PCM and the throttle body can interrupt the actuator motor drive circuits or the position sensor signals, causing the PCM to interpret the plate as stuck.
The TPS reports actual throttle plate position back to the PCM. A failed or out-of-spec sensor can return a stuck-closed reading even when the plate is moving, setting P2112 along with TPS-related codes.
If the APP sensor signal is lost, erratic, or out of range, the PCM may default the throttle command toward closed as a failsafe, which can appear as a stuck-closed condition.
A software calibration issue can set P2112, and on rare occasions an internal PCM fault can. The PCM is the least likely cause and should only be considered after the throttle body, sensors, and wiring have all been thoroughly ruled out.
Almost never. P2112 is a throttle actuator system code, and in the vast majority of cases the real cause is a mechanical throttle body issue, a wiring fault, or a failed position sensor. The PCM should be considered a suspect only after all of those have been tested and eliminated.
The vehicle will usually enter a reduced-power or limp mode and can generally be driven at low speed to a repair facility, but throttle response will be severely limited and the engine may stall. Extended driving is not recommended.
If carbon buildup is what is physically preventing the plate from opening, a proper throttle body cleaning can restore normal operation. However, if the actuator motor, internal gear, or position sensor has failed, cleaning will not help and the throttle body will need repair or replacement.
No. P0122 and P2135 are throttle position sensor circuit and correlation faults, while P2112 specifically means the PCM has detected a functional or mechanical failure where the throttle plate is stuck closed and not following the commanded position.