P0121 on Chevrolet vehicles The throttle position sensor and the engine's behaviour disagree
P0121 is named on 8 Chevrolet model years (2016–2026): 9 manufacturer filings and 0 owner reports in NHTSA’s files, across Express, Corvette, Silverado 2500HD, Silverado 3500HD, Trailblazer.
Which Chevrolet model years name P0121
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2016 Chevrolet Express | Electrical System | 2 | — |
| 2026 Chevrolet Trailblazer | Not specified | 1 | — |
| 2018 Chevrolet Corvette | Engine | 1 | — |
| 2018 Chevrolet Silverado 3500HD | Engine | 1 | — |
| 2017 Chevrolet Express | Engine | 1 | — |
| 2017 Chevrolet Silverado 2500HD | Engine | 1 | — |
| 2017 Chevrolet Silverado 3500HD | Engine | 1 | — |
| 2016 Chevrolet Silverado 3500HD | Engine | 1 | — |
A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.
Chevrolet filings that name P0121
Source: NHTSA manufacturer communicationsBulletins and campaigns Chevrolet filed with NHTSA whose summary names P0121. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 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.
- 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- This PI was superseded to update model years and add information concerning idle surge, reduced engine power mode, and/or DTCs P0068, P0121, P1516, P2101, P2119, and/or P2176 that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.
- 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.
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. The record above is what Chevrolet and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs P0121 a known problem on Chevrolet vehicles?
It is a documented one: NHTSA's files hold 9 manufacturer filings and 0 owner reports naming P0121 on 8 Chevrolet model years (2016–2026). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.
Which Chevrolet models does P0121 appear on most?
2016 Express (2 documents), 2018 Corvette (1 document), 2017 Express (1 document).
Does P0121 on a Chevrolet mean it is recalled?
No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.