What it means
The control system has detected a condition that requires the engine to be shut down. The code identifies a commanded shutdown response; it does not specify that throttle position sensors disagree or that the motor is uncontrollable.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The throttle actuator control system can command an engine shutdown when it detects a condition it considers unsafe. P2105 indicates that shutdown response was commanded; the code alone does not identify which fault triggered it or prove that the throttle-position sensors disagree.
Common causes
Most likely first.
- TPS1 and TPS2 disagree beyond limit
- Throttle motor not controllable
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Preserve freeze-frame data and scan for related throttle, pedal, and engine-control codes to find the condition that prompted the shutdown command.
- Check whether the engine starts and runs consistently, and review live throttle and pedal signals for implausible or missing readings.
- Inspect the throttle body, pedal and throttle connectors, and related wiring for looseness, corrosion, or visible damage.
- Test the circuits named by companion codes using the wiring diagram and manufacturer's procedure, including throttle-position feedback if indicated.
- Repair the confirmed underlying fault and verify the system no longer commands shutdown before returning the vehicle to service.
Common fixes
- Repair the throttle-position, pedal-signal, or actuator fault confirmed by diagnosis.
- Reconnect or repair damaged, loose, or corroded throttle and pedal wiring.
- Replace a failed throttle actuator or sensor only when testing confirms it is defective.
- Address a control-module fault only after its power, grounds, wiring, and software have been checked.
Can I keep driving?
Treat an unexpected shutdown or repeated shutdown command as unsafe: do not drive in traffic, because loss of engine power can leave the vehicle difficult to control. Arrange recovery and have the cause diagnosed before driving again.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.