Advancetrack w/RSC braking problem

[Jim Summerville]

2006 Explorer XLT EB 187,500 miles V8 4X4. Backed out of driveway, heard a noise from rear end. Drove about 300 feet and ABS and skid light came on. Tool image showed up on intrument cluster. Pushed reset and all OK. Over last two weeks those lights would come on occasionally. We currently have snow packed streets and slush, north Missouri. Now the lights come on and car self brakes eventhough i am going straigth with no apparent tracktion or sliding problem. This braking causes noises and brings car to almost a dead stop right in the middle of traffic. It will speed up some then slow down again but after 30 seconds or so it will let me speed up to streets speed, like 30mph. A half a mile latter it may slow me down again.
Sometimes i see the 4X4 dash light up automatically. When i brake they work normally, no noise or pulling to side and the ABS pulsing the pedal is normal when i brake on a slick surface.

 

[FR-425]

The "tool" flash means a fault code was saved.

Is it All Wheel Drive? (no 2wd on the selector switch)

I ask that question to ask another.

Have you recently changed only two of the tires?

AWD will act a fool with different size tires front-to-rear.

It will cause the transfer case to bind and the difference in wheel speed in the snow will freak out the ABS and traction control.

 

[Jim Summerville]

It is a 4X4.
I have not changed tires. OEM size tires and been on car for 2 years and in very good condition.

 

[1Aauto]

Welcome to the site.:wavey:

 

[FR-425]

Does it behave the same in 2wd?

 

[Jim Summerville]

FR-425. I do not have a 2X select button. It is always in 4X4, maybe it automatically selects 2X or 4X, that is its default. I have three buttons, the default 4X, high 4X, and Low 4X. I was having the problem in the default and high 4X. One time in the default mode, the high 4X showed up on its own on the instrument panel light and the brakes automatically activated and brought me almost to a dead stop. I pushed the default button and it was still braking and then a short distance latter it was normal.
Main streets in town dried up pretty good yesterday and I had no issues in the default mode. It is snowing again so I will get more opportunities to check out the problem in the next couple of days.

 

[FR-425]

Ok,

When in "default" 4X the vehicle is in 2wd until traction control detects wheel spin, then it will engage 4X4 automatically.

When you select "High 4X it operates as normal 4X4. Low is also Normal 4X4 and will not engage unless the vehicle is at full stop with trans in nuetral.

So it does sound like a traction control glitch, running in "High 4X" (manual 4X4) should clear it up.

You do however need to pull the computer codes to get more info on the traction control issue. The ABS is used as "input" for the traction control so the two are related. (likely a bad ABS wheel speed sensor)

You can post the codes up here for more help with diagnosis.

Any auto parts store can read the codes for you.

 

[Jim Summerville]

Will get the codes. Have about 12" of snow to deal with for now. I have the same breaking issue in High 4X.

 

[Jim Summerville]

FR-245.
O'Reily checked code. My front left speed sensor is bad. O'Reily clerk first told me I had to buy the wheel bearing and sensor as one at $348 or $216. I asked him to check closer and he found out the sensor is available stand alone at $162.00. Price from Silver Streak Ford is $105.00+ SH.
Now I am looking for instructions or video on doing it myself.
Thanks for you help.