This is my second post trying to get help on this topic last one had no reply, I have a 93 f150 4x4 with rear abs the abs, light comes on for the gauge check goes off for a second then remains on solid. this truck had been sitting for approx 3 years not running. I went through the brake system and replaced all the pads and shoes had the drums and rotors resurfaced and replaced the rear wheel cyls that were bad and one steal brake line and all the rubber lines (dry rotted). all new fluid. the trucks brakes stop excellent even under a panic stop the wheels do not lock up. all the relays are fine and through a resistance test the rear axle sensor appears to be working (ohms reading fluctuated as axle was turned). any sugestions? this is the best stopping ford truck I have had yet and I have had a bunch of ford trucks (mostly 78-79s), so I don't know why the abs light is staying on. does any body even know how to get the abs codes??? I think it is RABS1. or how to test abs actuator? or how to disable abs system and dash light. with all the ford trucks that have this system there must be sombody out there that has had this problem and can advise--thanks

 

dont know if this will help you or not but The abs light on my explorer stays on too, I was told that it could be metal shavings getting stuck on the abs sensor causing it to come on, i havent replaced the sensor so i dont know if it is my problem or not

 

Actually I pulled the sensor to clean it and I did find a metal shaving on it--though I cleaned it and after changed the diff fluid so maybe that caused the light don't know, why it is not resetting even after I have disconected the battery for a couple hours is beyond me --thanks for the input

 

Do you actually feel the abs kicking on in the rear when you stop? My abs pump broke when I was chinging a line going to it. It was so rotted the fitting split the housing. I just bypassed it, I dont get a light. Did you ck to see if there is a fuse for the abs? Ck the wires at the abs pump(along the frame rail under drivers side door) and ck the connection at the rear sensor. Have you checked the abs ring? on the ring gear inside the rear diff, might have a broken tooth and causing the code to come on. I dont think that would happen tho.

 

I don't feel a pulsation in the pedal when the brakes are in panic stop. but it does stop fast. I guess maybe I should put some weight in the bed and see if it acts the same. the modulator doesn't look bad at all not crusty - infact the bleeder nicely cracked open for the bleeding process. in fact even though it was sitting it is a 4x4 so it is high enough off the ground were it is not punky, the line I had to replace was crushed flat by a tow truck's hook. I have checked all the under dash fuses. and when I had the diff cover off the ring looked good. how do you check the modulator? should it have 12v going to it or something? so you bypassed the whole unit via metal barake line and now the abs light does not come on? did you leave the wiring in place?

 

For the codes take a look at post-number 6 in this Thread:

https://www.ford-trucks.com/forums/6...?highlight=abs

The plugs in the rest of the post may be wrong (they are for a Bronco) but I will post the right ones for your truck if you need them.

 

Yes I just left the wiring, but I guess the pump is good on my truck, so even if you bypass yours that wont help any. See whats codes you have then let us know.

 

Thanks looks like the bronco is 4wl abs If the plug is similar would the contacts on it be the same for a 2w abs? if you would I would like the post of the one for the 93 truck rabs, I am afraid to short out something. the procedure looks pretty simple thanks again

 

Also were is that connector supposed to be?--the only connector that I could see that looked similer is the eec conector or the one on the abs computer under the dash. the modulator has a round connector and underneath the master cyl there is a sqaure connector that looks like is connected to the modulator and resv sensor

 

From the 1993 Ford Truck Shop Manual for the F150.


Obtaining the Diagnostic Trouble Code (DTC)

NOTE:
Verify the ignition switch is in the RUN position. (NOTE: 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. If grounding this wire does not start the REAR ABS lamp flashing, go to System Pre-Check «Test D» , Yellow REAR ABS Light Self-check OK, but no flashout code when diagnostics is started.

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 module detects normal system operation.



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ok i got a code 12 from the abs, from what I could find appears to be a fluid leak on abs on a panic stop. Also the "red" brake warning light is also not comming on with key on or run position. it does come on when e brake is applied. I grounded the middle wire on fluid level sensor and the light came on, when i jumped the to color wires together to as I figure would by pass the sensor i get nothing. as too the abs trouble code I don't understand I had a bad wheel cyl but that was replaced as wells as lines and the system is holding good pressure. when you mash and hold the pedal down with a lot of force (not running) it does not move or give at all--as I assume it would if there was a leak. I am thinking what ever checks this pressure level may itself be bad--or stuck from the last problem again the truck was sitting for a few years. I have also disconnected the battery multiple times and this code keeps comming back so I assume I am wiping the KAM memory when battery is off. when reconnected (battery) the abs trouble light after self test comes right back on and stays solid ---so Any sugestions were I should go from here? and any Idea how to check pressure sensor? thanks again

 

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Description

Code 12 is generated when the module detects that the brake fluid level in the master cylinder reservoir is low for one or more seconds during an anti-lock stop. It can also be generated by a short in the stoplamp circuit.

Possible Contributing Base Brake Component/Vehicle Wiring Concerns

Low master cylinder fill level.
Fluid leaks in vehicle brake system.
Worn or damaged master cylinder fluid level switch, or fluid level circuit shorted to ground.
Master cylinder float that sticks in the bottom of reservoir or does not float.
Failed diode-resistor element in stoplamp circuit.

 

OK thank you for the info--- how do I test the Failed diode-resistor element in stoplamp circuit. as I wrote in previous post I think there is a problem in the circuit since "red" light does not self check just comes on with e brake. where is that resistor located? in the master fues panel under the hood? I plan to try to follow the wiring from master to fues to try to narrow down this issue. I know the master is full and the float is not sticking as well as there does not appear to be any line leaks. what do you think about running a resistance test on the fluid level sensor between the two colored (non black) wires and moving the float with a screw driver--I would guess that sould give some sort or reading if it was working-right? thanks again for your help.

 

I've got this exact problem on my truck. Same code and same circumstances. The only thing I've been able to find on mine is the connector for the fluid level switch has a short in the harness, but when I bend the wire to make full contact, the ABS light will still come on regardless. The rest of the system is in good shape so I'm open for ideas as well

 

See Diagram below.

LH (driver's side) rear of engine compartment, taped in harness near C202 (B9) for the 4.9 engine.



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