Hello All,

I want to start out by saying Hi, I am a newbie to the site.

I hope someone has had this problem or just plain knows were I can turn. I have a 98 F150 4x4 75,000 miles with only rear ABS and both the ABS and brake warning lights are on, I have replaced the speed sensor in (on) the rear differential checked the relays, fuses, connections after reading several posts about them maybe being the culprit but the lights are are still on, I checked the ABS code and the code that came back was 4 Open/Grounded RABS Valve Reset Circuit. I have no idea where to look next, please any suggestions. Should I bite the bullet and take it to the dealership and spend my life savings repairing it? or is there something more I can look at?

 

You better be grateful,...here are the 13 steps for code 4.

1) Turn ignition off. Disconnect neg. battery terminal. Disconnect control module connector. Gently pull on terminal No.6 (light blue/red wire) of control module and control harness connector. If the connector terminal is fully engaged and corresponding terminal of control module is okay, leave control module disconnected and go to the next step. If terminal is loose or has pulled out of connector, repair or replace terminal or connector as necessary and go to step 12. If control terminal is loose, bent, deformed, corroded or missing, replace control module and go to step 12.

2) Disconnect and inspect 4-pin valve assembly connector. Valve assembly is located on left frame rail, towards the rear of the engine compartment. Gently pull back on terminal 2 (light blue/red wire) and terminal 3 (black/white wire) of valve assembly connector and valve assembly harness connector. If terminals are fully engaged in connector, leave valve assembly disconnected and go to the next step. If terminals are loose or have pulled out of connector, repair or replace terminals or connector as necessary and go to step 12. If valve assembly terminals are loose, bent, corroded or missing, replace valve assembly and go to step 12.

3) Using an ohmmeter, measure the resistance of Light Blue/Red wire between control module harness and connector terminal 6 and valve assembly harness connector terminal 2. If resistance is less than 10 Ohms, go to next step If resistance is greater than 10 ohms, repair open in Light Blue/Red wire and go to step 12.

4) Using an Ohmmeter, measure resistance between terminal 3 (Black/White wire) of valve assembly harness connector and ground. If the resistance is less than 3 Ohms go to next step. If the resistance is graeter than 3 Ohms repair the wire and go to step 12.

5) Using an Ohmmeter, measure the resistance between terminal 6 (Light Blue/Red wire) of control module harness connector and ground. If resistance is more than 12 ohms, go to next step. If resistance is less than 12 ohms, repair short to ground in the wire and go to step 12.

6) Using an ohmmeter, measure resistance between terminal 2 (reset) of the valve connector and valve body (ground.) Ifresistance is more than 10 k/ohms go to step 8. If resistance is less than 10 k/ohms, replace valve assembly and go to step 12.

7) DEALS WITH AEROSTAR AND RANGER (OMITTED)

8) Measure resistance between terminal 2 and terminal 3 of valve assembly connector. If resistance is more than 10 k/ohms go to step 10. If resistance is less than 10k/ohms, replace valve assembly and go to step 12.

9) DEALS WITH AEROSTAR AND RANGER (OMITTED)

10) Perform testing under INTERMITTENT DIAGNOSIS. If intermittent open is found, repair as necessary and go to step 12.

**If you need that step email me**

11) Ensure all preceding diagnistic steps have been completed and involving wiring integrity has been verified. If not go to last diagnostic step completed and continue from there. If all diagnostic steps have been completed, replace control modeule and go to next step. If control module has already been replaced with no resolution of problem, replace valve assembly and go to next step.

12) Ensure ignition if off. Reconnect negative battery cable. Ensure all connectors are secure. retrieve trouble codes. If Code 16 is present go to code 16 under TEST DRIVE. If code 4 is present, go to next step. If any other trouble code is present, go to appropriate test for corresponding trouble code.

**If you need those tests email me**

13) Ensure all preceding diagnostic steps have been completed, and involved wiring integrity has been verified. If not, go to last diagnostic step completed and continue from there. If all diagnostic steps have been completed, go to nect step.

14) If previous diagnostic steps have been completed, problem is most likely wiring related. Go to INTERMITTENT DIAGNOSIS and preform tests on involved circuits. If problem is not resolved, go to step 11. If problem is resolved, repair is complete. Go to CODE 16 under TEST DRIVE. For additional testing, see CODE 4 under TEST DRIVE.

**If you need that step email me**

I hope this helps...

Taken from "raybestos ABS service manual" #DA-R-97

 

Colorado Osprey,

THANK YOU SO MUCH!!

That is exactly the information I was looking for.