Hello, I have a 1999 f150 4.2l that the abs light comes on going slow, under 25mph. Replaced speed sensor still there. Hook up my scan tool and get connection error. Only in abs mode. Check fuses and power point's. Scanner works on a buick fine. Any help would be great.

 

You have to check the single fuse for the cigar lighter, nothing else.

That is ambiguous. Please clarify what you actually mean.

 

With the scan tool connected to the obd connection. The only time I get the connection error is when I scan for the abs codes. Fuses are good.

 

Are you sure you have 4wheel abs? Rear abs does not connect to the OBDII port.

 

Does your scanner even support ABS scanning for the particular vehicle in question?

 

Yes it supports my model. Yes it is 2 wheel anti lock.

 

Not if you have RABS since, as 70f150longbed already noted, the RABS module isn't connected to the DLC. You have to use the lamp flash codes to pull fault DTCs from the RABS module.

 

Thank you I will do that then. Had checked other threads did not see that one from 70f100longbed.

 

Resolution -

I need a replacement ECM or my current one needs to be reflashed. My truck starts, runs, and drives for now - I'm not playing with it.
On the ABS front, there is not ABS code reader for this year. You have to short the wire and read the blinking codes. I my case is blinked 12 times and I replaced the master cylinder. The sensor at the bottom of the master cylinder was corroded.