Questions and Answers

Ford F-150 Air Bag Codes Q. The air bag light flashes a 51 code all the time. Local mechanics say they don't have a clue and I am quite a ways from a Ford dealer. Is this something I can fix? 1994 Ford F-150. Thanks, Larry

A. The code 51 means nothing at this point. That's why none of the mechanics around have a clue. We have to retrieve the codes from the computer.

Retrieving Diagnostic Codes:

NOTE: Verify the ignition switch is in the RUN position (engine does not need to be running). Next, locate the black RABS II diagnostic connector. The diagnostic connector has two mating halves (one of which has a black/orange wire connected to it). Disconnect the two halves.

Attach one end of a jumper wire to the black with orange stripe wire side of the diagnostic connector. Momentarily ground the opposite end of the jumper wire by connecting it to a good chassis ground for 1-2 seconds. Grounding this wire should start the REAR ABS lamp flashing.

CAUTION: Care must be taken to connect only the black/orange stripe wire to ground. Connecting the mating connector wire to ground will result in a blown fuse.

The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates diagnostic trouble Code 4. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times. This code will be used later for system repair instructions. It should be written down for future use. A diagnostic trouble code of 16 will be obtained when the antilock electronic control unit detects normal system operation.

The last step of the system test always includes clearing the Keep Alive Memory (KAM). To do this, simply turn off the ignition while the diagnostic connector halves are separated as described in the procedures for obtaining the diagnostic trouble code, after which the diagnostic connector should be re-assembled to provide KAM power to the antilock electronic control unit.

Once we know what the codes are, we can go from there. Another thing just dawned on me, if the ABS system is in self diagnostic mode, the code 51 could actually be a code 16 which indicates normal operation.