Cause
Carbon deposits in the throttle body
Deposits around the throttle plate, mostly delivered by the crankcase breather and exhaust gas recirculation. They narrow the airway the module has learned, so the engine gets less air than commanded at small openings — idle first, since that is where the plate is nearly shut. Cleaning it without resetting the learned position leaves the same complaint, which is how a cleaned throttle body gets replaced.
Typically an easy fix. Often worth checking before paying anyone to look.
Some of these codes mean you should stop driving
12 of the 29 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 (29)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Likely for this code Stop driving High
- P0221 Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance Likely for this code Stop driving High
- P0505 Idle Air Control System Likely for this code Moderate
- P0506 Idle Air Control System RPM Lower Than Expected Likely for this code Moderate
- P0519 Idle Air Control System Performance Likely for this code Moderate
- P0638 Throttle Actuator Control Range/Performance — Bank 1 Likely for this code High
- P0639 Throttle Actuator Control Range/Performance — Bank 2 Likely for this code High
- P2101 Throttle Actuator A Control Motor Circuit Range/Performance Likely for this code Stop driving High
- P2104 Throttle Actuator Control System — Forced Idle Likely for this code Stop driving High
- P2106 Throttle Actuator Control System — Forced Limited Power Likely for this code High
- P2108 Throttle Actuator A Control Module Performance Likely for this code Stop driving High
- P2109 Throttle/Pedal Position Sensor A Minimum Stop Performance Likely for this code Moderate
- P2110 Throttle Actuator A Control System — Forced Limited RPM Likely for this code High
- P2111 Throttle Actuator A Control System — Stuck Open Likely for this code Stop driving Critical
- P2112 Throttle Actuator A Control System — Stuck Closed Likely for this code Stop driving High
- P2113 Throttle/Pedal Position Sensor B Minimum Stop Performance Likely for this code Moderate
- P2115 Throttle/Pedal Position Sensor D Minimum Stop Performance Likely for this code Moderate
- P2116 Throttle/Pedal Position Sensor E Minimum Stop Performance Likely for this code Moderate
- P2117 Throttle/Pedal Position Sensor F Minimum Stop Performance Likely for this code Moderate
- P2118 Throttle Actuator A Control Motor Current Range/Performance Likely for this code High
- P2119 Throttle Actuator A Control Throttle Body Range/Performance Likely for this code Stop driving High
- P0068 Manifold Absolute Pressure/Mass Air Flow — Throttle Position Correlation Stop driving High
- P0101 Mass or Volume Air Flow Sensor A Circuit Range/Performance High
- P0226 Throttle/Pedal Position Sensor/Switch C Circuit Range/Performance Stop driving High
- P0510 Closed Throttle Position Switch Low
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
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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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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