P1633 on the 1999 Ford Escort
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.
| 996111 | 1999-09-09. Service bulletin. SOME VEHICLES MAY EXHIBIT A MALFUNCTION INDICATOR LIGHT (MIL) AND DIAGNOSTIC TROUBLE CODE (DTC) P1633 IN MEMORY. *TT |
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1 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.