P0638
1 owner report and 9 manufacturer filings across 4 model years from Hyundai, Mazda.
Where P0638 shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2018 Mazda CX-9 | Electrical System | 3 | — | Battery → |
| 2017 Mazda CX-9 | Electrical System | 3 | — | Battery → |
| 2016 Mazda CX-9 | Electrical System | 3 | — | Battery → |
| 2018 Hyundai Sonata | Service Brakes | — | 1 | Brake pads → |
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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What it gets filed under
What owners said
Source: NHTSA complaint databaseOwners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.
Technitia found code( P0638 ) active code and (p211935002a00 throttle body carbon cleaning- adjustment and found rubber grommet stuck in the throttle body roved grommet
9 manufacturer filings name P0638. 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 P0638.
- 01-001-20-3650 Service bulletin2020-01-09 · Electrical System
- After parking the vehicle in temperatures below freezing, some customers may experience a lack of power with the check engine light on and DTCs P0638:00 and/or P2112:00 stored in memory. - P0638:00: Throttle valve actuator control range/performance problem (one drive cycle DTC) - P2112:00: Throttle valve actuator motor current range/performance problem (one drive cycle DTC) This concern may be cau
- 01-001-18-3419a Service bulletin2018-08-09 · Engine And Engine Cooling — Exhaust System — Manifold/Header/Muffler/Tail Pipe
- After parking the vehicle at temperatures below the freezing, some customers may experience a lack of power with the check engine light on and DTC P0638:00 and/or P2112:00 stored in memory. - P0638:00: Throttle valve actuator control range/performance problem (one drive cycle DTC) - P2112:00: Throttle valve actuator motor current range/performance problem (one drive cycle DTC) This concern may be
- 01-001-18-3419 Service bulletin2018-01-24 · Electrical System
- After parking the vehicle at temperatures below the freezing, some customers may experience a lack of power with the check engine light on and DTC P0638:00 and/or P2112:00 stored in memory. - P0638:00: Throttle valve actuator control range/performance problem (one drive cycle DTC) - P2112:00: Throttle valve actuator motor currentrange/performance problem (one drive cycle DTC) This concern may be c
What P0638 means
Source: SAE J2012 / OBD-IIP0638 sits in the generic range of the OBD-II standard, so it means the same thing on every vehicle sold in the United States — but WhichTrim does not carry a definition for it and will not invent one. What is on this page is the record: who named it and on what.
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 P0638
Source: NHTSA files and the OBD-II standardCan I keep driving with P0638 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.