P0121 The throttle position sensor and the engine's behaviour disagree
0 owner reports and 23 manufacturer filings across 17 model years from Buick, Cadillac, Chevrolet, GMC.
Where P0121 shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2017 Cadillac CTS | Engine | 3 | — | Throttle body → |
| 2016 Cadillac CTS | Engine | 3 | — | Throttle body → |
| 2016 Chevrolet Express | Electrical System | 2 | — | Throttle body → |
| 2016 GMC Savana | Electrical System | 2 | — | Throttle body → |
| 2026 Buick Encore | Not specified | 1 | — | Throttle body → |
| 2018 Cadillac CTS | Engine | 1 | — | Throttle body → |
| 2018 Chevrolet Corvette | Engine | 1 | — | Throttle body → |
| 2017 Chevrolet Express | Engine | 1 | — | Throttle body → |
| 2017 Chevrolet Silverado 2500HD | Engine | 1 | — | Throttle body → |
| 2018 Chevrolet Silverado 3500HD | Engine | 1 | — | Throttle body → |
| 2017 Chevrolet Silverado 3500HD | Engine | 1 | — | Throttle body → |
| 2016 Chevrolet Silverado 3500HD | Engine | 1 | — | Throttle body → |
| 2026 Chevrolet Trailblazer | Not specified | 1 | — | Throttle body → |
| 2017 GMC Savana | Engine | 1 | — | Throttle body → |
| 2017 GMC Sierra 2500HD | Engine | 1 | — | Throttle body → |
| 2017 GMC Sierra 3500HD | Engine | 1 | — | Throttle body → |
| 2016 GMC Sierra 3500HD | Engine | 1 | — | Throttle body → |
A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
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P0121 by make
The same record, one make at a time: the model years, bulletins and owner reports that name P0121 on that maker’s vehicles.
What it gets filed under
23 manufacturer filings name P0121. Start with what the maker wrote down.
A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names P0121.
- PIP6112 Service bulletin2026-05-04 · Unknown Or Other
- This Preliminary information communicates to the technician the diagnostic direction necessary to address MIL illumination with DTCs P0121, P0299, P1101 or P00C7.
- PIP4578B Service bulletin2017-12-18 · Engine And Engine Cooling
- This PI was superseded to update model years and add information concerning idle surge, reduced engine power mode, and/or DTCs P0068, P0121, P1516, P2101, P2119, and/or P2176 that may be experienced on high mileage vehicles. Please discard PIP4578.
- PIP5424A Service bulletin2016-10-05 · Equipment — Other — Owners/Service/Other Manual
- This Preliminary Information communication provides information to the technician about vehicles that the engine may shut off after wide open throttle maneuvers also the Service Engine Soon Malfunction Indicator Lamp on. Technician may find Diagnostic Trouble Codes P0121, P2101 and P2119 set. Dealer should inspect the air-filter to make sure it is correct. Technician should replace the air filter
- PIP5424 Service bulletin2016-09-23 · Engine
- THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT THE ENGINE MAY SHUT OFF AFTER WIDE OPEN THROTTLE MANEUVERS ALSO THE SERVICE ENGINE SOON MALFUNCTION INDICATOR LAMP ON. TECHNICIAN MAY FIND DIAGNOSTIC TROUBLE CODES P0121, P2101 AND P2119 SET. DEALER SHOULD COMMUNICATE TO THE CUSTOMER NOT TO DRIVE THE VEHICLE AGGRESSIVELY ON TRACK LIKE CONDITIONS.
- PI1538 Service bulletin2015-10-01 · Electrical System
- This preliminary informational bulletin provides repair information on Engine Control Module (ECM) reprogramming to correct a customer concern of experiencing a slight hesitation and/or sag. Upon further inspection, DTCs P0101, P0106, P0121, P1101 may be set.
What P0121 means
Source: SAE J2012 / OBD-IIThe throttle position sensor and the engine's behaviour disagree.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about P0121
Source: NHTSA files and the OBD-II standardCan I keep driving with P0121 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.