Electrical Gremlin? Autotrac issue

[R W Carpenter]

So, over the last week or so my 06 Limited has developed a weird issue. I think I might know what it is. First though I would like to describe the issue and then share what I think the issue may be and solicit opinions.

ISSUE:

When driving the truck (usually when it is cold outside) all of the dash lights will start to flicker (including the radio) and the message center will beep at me as the RSC, Brake and ABS lights flash then everything will go back to normal and the message center will display the Autotrack on message. When this happens the radio will cut out and then come back on as well. Turning off the Autotrack does not bring about any chance except that after the flicker/flash happens the Autotrack on does not display on the message center which is to be expected since it is turned off.

New today is that sometimes when I depress the brake pedal the above issues occur. This aspect of the problem just started today.

I suspect the switch on the brake pedal for that controls the brake lights and shifter interlock as the issue. Can't say for sure though.

So, I ran my OBDII tester and got the following ABS codes (No codes in other modules at this time):

B1676 Battery Pack Voltage Out of Range
C2778 Sensor Power Supply Failure
U2023 Malfunction Received From External Node
B1483 Brake Pedal Input Circuit Malfunction

Thinking I should start with replacing the switch on the brake pedal and see if the problem resolves itself?
My thought process is that if the switch is bad that it could be causing the other codes?

Any thought or experience with this type of issue are appreciated.

I am going to do a bit of research online on these codes and will report any findings.

 

[stamp11127]

Get the wiring diagrams and troubleshoot it the right way. Tossing parts is usually a waste of time and money.
Why would the brake switch affect the radio?

 

[R W Carpenter]

Immediately after writing the post I remembered that I had bought the service manual so I broke it out and looked up the first code (B1676). It said to check the voltage on the battery with the key on and engine off as well as key on engine on. The voltages were both under what the service manual said they should be. So, I took the truck over to AAA and had them test it. Originally, they did the ol' in the parking lot test and the voltage came back normal so they suggested testing the starter and alternator (no charge) so I let them do that. They tested those and they were normal. They then retested the battery with a full diagnostic machine and it turned out it was under voltage. So, $157 later I have a new battery. On the short drive home the gremlin didn't rear it's ugly head so hopefully the problem has been solved. Got to go out and clear all the old codes and drive it a couple of days and see what happens.

 

[stamp11127]

If the expy has been starting without issue - not cranking slowly, the battery may not have been the problem. The new "fancy" testers will give a status of the battery such as CA & CCA as compared to the rating when original. An example would be the battery is rated for 900 CCA but tests out at 200 CCA, then you have a problem.
The battery acts as an electron sponge with the alternator providing the power to run the electronics and other circuits. They are classified as SLI - starting, lighting & ignition and provide power when the engine isn't running.
For those that doubt this, check the voltage on a circuit with the engine running. The value should fall between 13.5 - 14.6 volts, which is being provided by alternator.

What were your voltage readings?

 

[R W Carpenter]

The CCA reading was the issue that they pointed out. Forgot to put that in my previous post.

Cleared all the old codes and ran new code check. Now I get C1998 Module Calibration Incomplete. Called Ford $120. I know I can't fix this one myself as I don't have the diagnostic equipment to do it. Guess I am stuck with the flashing light on the dash for awhile until I can afford to pay Ford to calibrate everything. Gotta love it. In the end looking at almost $300 dollars all because of a bad battery. Should have just bought another XLT without all the bells and whistles instead of the Limited. Live and learn Ii suppose.

 

[R W Carpenter]

Update:

Called a mechanic I do business with every so often (non dealership mechanic) and told him what was going on. He told me to bring it by and he'd have a crack at it. He was able to recalibrate the module. It was the ABS module by the way. So all is fixed and good now. And the best part is HE DID IT FOR FREE. Screw you Ford and your $120 charge for 5 minutes worth of work.