P21CD
0 owner reports and 36 manufacturer filings across 9 model years from Ford.
Where P21CD shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2019 Ford F-250 Super Duty | Electrical System | 4 | — | Battery → |
| 2018 Ford F-250 Super Duty | Electrical System | 4 | — | Battery → |
| 2017 Ford F-250 Super Duty | Electrical System | 4 | — | Battery → |
| 2019 Ford F-350 Super Duty | Electrical System | 4 | — | Battery → |
| 2018 Ford F-350 Super Duty | Electrical System | 4 | — | Battery → |
| 2017 Ford F-350 Super Duty | Power Train | 4 | — | |
| 2019 Ford F-450 Super Duty | Engine | 4 | — | |
| 2018 Ford F-450 Super Duty | Electrical System | 4 | — | Battery → |
| 2017 Ford F-450 Super Duty | Electrical System | 4 | — | Battery → |
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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P21CD by make
The same record, one make at a time: the model years, bulletins and owner reports that name P21CD on that maker’s vehicles.
What it gets filed under
36 manufacturer filings name P21CD. 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 P21CD.
- TSB 22-2191 Service bulletin2022-05-17 · Electrical System
- Some 2018-2021 F-150 vehicles equipped with a 3.0L diesel engine, 2016-2022 F-650/F-750 vehicles equipped with a 6.7L engine, and 2017-2022 F-Super Duty vehicles equipped with a 6.7L engine and built on or before 08-Mar-2022 may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) P21DD, P20BA. P20B9, P204C, P208A, P208B, P208C, P203B, P205B, P21CD and/or U0
- TSB 21-2336 Service bulletin2021-09-28 · Electrical System
- Some 2018-2020 F-150 vehicles built on or before 1-Apr-2020 equipped with a 3.0L diesel engine, 2017-2019 F-Super Duty vehicles built on or before 30-Oct-2019 equipped with a 6.7L engine and 2016-2019 F-650/F-750 vehicles built on or before 30-Oct-2019 equipped with a 6.7L engine may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) P21DD, P20BA. P20B9, P
- TSB 19-2315 Service bulletin2019-10-21 · Power Train
- Some 2017-2019 F-Super Duty vehicles built on or before 1-Aug-2018 equipped with a 6.7L engine may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) P21DD, P204C, P21CD and/or U02A2 in the powertrain control module (PCM). This may be due to water intrusion within connectors C3613 and/or C4851 on the reductant harness going to the reductant pump/heater ass
What P21CD means
Source: SAE J2012 / OBD-IIP21CD 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 P21CD
Source: NHTSA files and the OBD-II standardCan I keep driving with P21CD 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.