RABS Code 4, need help figuring it out

Bgunner said:

I have a 94 Ranger XLT super cab 4x2 with the ABS light on. I pulled the code and I get a code 4 but searching the internet I can not find a list of what the codes mean. As far as I can tell this code means "RABS valve switch closed or open dump valve."

This information was taken from a 91 Explorer and was hoping someone had a book handy to look it up to be sure this is the correct meaning for the code.

I was also wondering, if this is the proper diagnosis, is the valve repairable or will I have to shell out about $130 for the valve assembly to have RABS back?

Some background on the light and truck: I purchased the truck in August of last year and the light was on when I bought it. The person who owned it before ran the truck for about a year and a half with the light on. Before this the truck was stored in climate controlled storage next to classic cars for about 3 years. My understanding is the light was on this whole time. The vehicle was purchased brand new in Virginia and spent most of its life there and only has 145,000 miles on it.

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Bgunner said:

Thank you so much for the pic of the codes. To go further into the issue, The rear wheel cylinders on both sides were leaking so I replaces them with new, along with a new break hose on the front and did a full break bleed and get the proper amount of fluid out of the rear, so at least there is no issue with fluid getting past the valves. The rear breaks work well as they will lock up. This is why I want the RABS in it because I live where it snows and the rear likes to come around when they do lock up.

I do not have the red break light on indicating low pressure or fluid. The light does work as it came on at times with the bad wheel cylinders in it and comes on every time I use the E-Break, I have a manual transmission so I use it all the time. I have changed the E-break switch and cleaned the connector at the master cylinder reservoir with electrical connector cleaner and time scraping.

Today, while the kid is in school, I'm going to take the connector off the valves and clean that along with trying to trace the wires to make sure there is no breaks or shorts.

Do you know of a way to test each solenoid valve to tell if they actually activate and move properly? This will help me tell if it is a valve issue or the module in the dash.

UPDATE: I grabbed my trusty multi meter and got 1.8 Ohms on the dump valve and 4.1 Ohms on the Isolation valve. As far as I know the Dump valve is supposed to be 1.2 ohms and the Isolation valve is supposed to be 4 ohms.

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Bgunner said:

If you are getting both lights then there is more than one issue, most likely. The red "Brake" light means low fluid in master, leak in the system some where OR possibly a bad switch on the master that reads the fluid level. First thing to look at is fluid level on the master cylinder to be sure it is not low. Next is to make sure the wiring at the switch is not corroded and has a good connection, this is located in the master cylinder reservoir. the last thing to check is there a leak in the lines, calipers and wheel cylinders? If all these check out then you may be looking at a bad master cylinder but this can only be determined after testing.

My RABS valves are shot so at this point I am not replacing the unit till the rest of things that are wrong are replaced. There is a computer that controls the RABS in these trucks. I would test this item before replacing more parts to be sure the rest of the system is working properly. This computer is located in the dash usually to the right side of the radio but if not hen located in that area between the radio and the ash try.

Resetting the Rabs valve: there is a rubber covered button on the valve body itself. Some times this will trip and need to be reset It takes some force to reset it once its tripped so a good hard push is necessary. If there is still air in your lines, If I had to guess as to where it would be in the valve body for the RABS, this could cause your BRAKE light on the dash to come on indicating low pressure in the system.

Click to expand...

Bgunner said:

If you are getting both lights then there is more than one issue, most likely. The red "Brake" light means low fluid in master, leak in the system some where OR possibly a bad switch on the master that reads the fluid level. First thing to look at is fluid level on the master cylinder to be sure it is not low. Next is to make sure the wiring at the switch is not corroded and has a good connection, this is located in the master cylinder reservoir. the last thing to check is there a leak in the lines, calipers and wheel cylinders? If all these check out then you may be looking at a bad master cylinder but this can only be determined after testing.

My RABS valves are shot so at this point I am not replacing the unit till the rest of things that are wrong are replaced. There is a computer that controls the RABS in these trucks. I would test this item before replacing more parts to be sure the rest of the system is working properly. This computer is located in the dash usually to the right side of the radio but if not hen located in that area between the radio and the ash try.

Resetting the Rabs valve: there is a rubber covered button on the valve body itself. Some times this will trip and need to be reset It takes some force to reset it once its tripped so a good hard push is necessary. If there is still air in your lines, If I had to guess as to where it would be in the valve body for the RABS, this could cause your BRAKE light on the dash to come on indicating low pressure in the system.

Click to expand...