Cause
Fault in the accelerator pedal position sensors
A fault in the sensors reporting where the driver's foot is, as distinct from those on the throttle body. The pedal is the input and the throttle is the output, and although they produce the same family of codes, they are separate assemblies and confusing them means replacing the wrong one.
Like the throttle sensors these are duplicated and cross-checked, and for a stronger reason: an unintended acceleration risk sits directly behind this signal. So the module's response to disagreement is deliberately severe — a reduced-power mode that limits the engine to little more than idle, which is alarming but correct.
The pedal assembly's environment is what fails it. It sits in the driver's footwell where water, salt and grit are carried in on shoes, so a corroded connector under the carpet is a frequent finding, and its harness is flexed by the pedal every time it moves. Check the connector and the harness before the sensor, and sweep the pedal slowly through its travel watching both signals — a dropout at one point with the other tracking smoothly is the sensor, while both misbehaving together points at the shared supply or earth.
Typically a moderate job.
Some of these codes mean you should stop driving
2 of the 4 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (4)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2104 Throttle Actuator Control System — Forced Idle Likely for this code Stop driving High
- P2105 Throttle Actuator Control System — Forced Engine Shutdown Likely for this code Stop driving Critical
- P2106 Throttle Actuator Control System — Forced Limited Power Likely for this code High
- P2110 Throttle Actuator A Control System — Forced Limited RPM Likely for this code High
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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