I have a 2006 XLT 4x4 with the 4.0L engine. I bought this truck 4 years ago, and the ABS light was on when I bought it. I'm now looking into fixing the ABS issues on this truck, but general web searches for solutions haven't turned up any useful information. I have an Innova 5410 code reader, which can read the ABS system codes, and it gave me the following codes:

C1148 - Right Front Wheel Speed Sensor Coherency Fault
C1158 - Left Front Wheel Speed Sensor Coherency Fault
C1186 - (ABS) power relay output open circuit
B1318 - Battery Voltage Low

Last summer, I ordered new ABS sensors all around, but I haven't installed them yet. When I saw the C1186 and B1318 error codes, I though the problem might be further upstream. Is the B1318 (battery low voltage) really specific to the ABS system, or are they talking about the main battery? This truck is my second vehicle, and because it sits for long periods of time w/o me driving it, the battery has gone dead on occasion, but I've replaced and/or replaced the battery and checked it with a volt meter when I got this error code. At the time I first saw the B1318 code, I checked my battery with a multimeter, and measured 12.6 - 12.9 VDC with the engine off at the battery terminals, and 14.2 - 14.5 VDC with the engine running. Even with all lights and accessories on, I was getting 14.4 VDC, so I don't think this error code is related to the main battery, and is specific to the ABS system, or that's a sign that the ABS system isn't getting any power at all, which may be the result of the C1186 error code.

For C1186, I can't find where that relay is. I have both the Chilton and Haynes manuals, and they are almost 100% identical in their content, and neither of them show the locations of the fuses/relays. I've read elsewhere online that this relay would be located on/in the ABS control module itself. Can anyone clue me in as to where this relay might be? I imagine if I knew where it was, I could pull the relay and check the power going into it with my multimeter and check the operation of the relay itself.

I know I can check the resistance of the sensors and the voltage being supplied to them with my multimeter, but if C1186 and/or B1318 means the ABS control module isn't getting the correct power, will this be a waste of time?

Thanks for your help.

 

Yes, no external relays
Unplug the 4WABS module in engine bay and look for corrosion on connectors and plug it back in, this cleans all the connectors

With this connector off you can use a Meter to test each sensor, use diagram to see which wires are for which sensors
Google: Test Ford ABS sensors
Lots of good info on what to look for

2006 4WABS wiring diagram below

You can check fuses 17 and 33 in engine fuse box, pull out the fuse and test voltage, maybe one of those has corrosion

B1318 - Battery Voltage Low, in a 2006 Ford Ranger may be corrosion in SJB(smart junction box) large connectors, cab fuse box is part of the SJB, need to pull off the passenger side kick panel to see the whole SJB
SJB is the "body computer"(BCM) in 2004 to 2011 Rangers, it replaced the GEM(1995-2003)

SJB has 4 larger wiring connectors that have been known to get moisture inside and cause odd issues and codes
Each has a lever to move that pulls them away from SJB so they can be removed and inspected