# P1635 on the 1999 Ford F\-250

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.

## Bulletins for this model year that name P1635

- [620269](https://open.wenmarpro.com/bulletins/620269), 2001-07-23: INOPERATIVE OR INACCURATE SPEEDOMETER AS WELL AS 4X4 LIGHT INOPERATIVE AND / OR DIAGNOSTIC TROUBLE CODE P1635 AND / OR P1639 AFTER A POWERTRAIN CONTROL MODULE \(PCM\) HAS BEEN REPLACED. \*TT
- [618529](https://open.wenmarpro.com/bulletins/618529), 2001-04-16: INOPERATIVE OR INACCURATE SPEEDOMETER, 4X4 LAMP ILLUMINATED AND / OR DIAGNOSTIC TROUBLE CODES \(DTCS\) P1635 OR P1639 PRESENT AFTER A POWERTRAIN CONTROL MODULE \(PCM\) OR INSTRUMENT CLUSTER REPLACEMENT. \*JB
- [613210](https://open.wenmarpro.com/bulletins/613210), 2000-06-19: CERTAIN VEHICLES MAY EXHIBIT AN INOPERATIVE SPEEDOMETER AND DIAGNOSTIC TROUBLE CODE P1635 AFTER A PECM HAS BEEN REPLACED. \*TT
- [613067](https://open.wenmarpro.com/bulletins/613067), 2000-06-16: SOME VEHICLES MAY EXHIBIT AN INOPERATIVE SPEEDOMETER AND DTC P1635 AFTER A PCM HAS BEEN REPLACED. \*MJS
- [612732](https://open.wenmarpro.com/bulletins/612732), 2000-06-12: ALL VEHICLES MAY EXHIBIT AN INOPERATIVE OR INACCURATE SPEEDOMETER, 4X4 LIGHT INOPERATIVE AND/OR DTC P1635 AFTER A PCM HAS BEEN REPLACED. \*MJS