Last post on Sep 15, 2013 at 8:46 AM
You are in the Dodge Dakota-2010 and older
What is this discussion about?
Dodge Dakota, Brakes, Truck
#166 of 184 Re: ABS and Brake light on [cheeze74]
Nov 09, 2011 (6:07 am)
ABS specific code 51 is REAR ISOLATION SOLENOID OPEN. this is applicable
to Dodge RWAL..it has nothing to do with any kind of relay.
Looking at the the 2000 wiring diagram for RWAL brakes, there is NO
relay associated with the CAB. I checked the PDC on my 1998 Dakota
and confirmed this,
The CAB is fused by a 40amp fuse in the PDC. So obviously if the lights
are coming on periodically, the CAB is getting battery power through that
fuse to operate. It has it's own separate ground connections G101.
There is also a 10amp fused ignition- run going to it. This would be coming
from the ignition switch I believe.
The rear wheel speed sensor comes into it and so does the CCD +/- data bus that it communcates with the PCM.
The brake pressure switch has it's own separate ground and comes in from
the proportioning valve. The CAB also senses the brake switch.
The ABS specific codes (read from the ABS controller diagnostic connector)
are: 21 to 90. Some are generic. Some are applicable to 4W ABS systems,
some to RWAL (like the dakotas) and some to internal ABS controller issues.
I don't have any specific wiring information on the K-H RWAL HCU..
but this link will give you a pretty good idea of how it works on the Dakota.
#167 of 184 Re: ABS and Brake light on [carverman]
Nov 09, 2011 (6:48 am)
The relay I was referring to is inside the CAB. I do have the shop manual for my 2000 Dakota but it doesn't give any detail on the CAB. If you are saying the code 51 is about the rear isolation solenoid being open, then I would assume it is sticking or has something inside it not allowing it to close completely. Do you know if this soleoind can be replaced seperatly or does the assembly have to be replaced. I reviewed the link on the RWAL and the codes they list do not show the codes I am getting. My shop manual does not list any codes in reference to the Anti lock system. Do you know where the list of codes can be found? Thanks again for your reply!
#168 of 184 Re: ABS and Brake light on [cheeze74]
Nov 09, 2011 (9:38 am)
I hate the editor on this site!
I had an answer all typed up and lost it.
Anyway, the K-H ABS control codes are NOT integrated with the OBDII diagnostic connector, as it was a proprietary RWAL ABS that most NA
vehicle manufacturers use. To read the ABS codes, you need an expensive
shop scan tool. ($2500). The CAB has it's own diagnostic connector for
As far as the ABS codes..the link below will give you a explanation for
each code once you enter the make,model, year and abs code.
(ABS codes 21 to 89)
http://www.wellsve.com/custom_searches/abs_troublecodes.php?make=Dodge&model=Dak- - - - - - - ota&year=2000&code=51&confirm=1&submit.x=21&submit.y=23
As far as I know the solenoid/valves on the K-H HCU are not individually
replaceable, and these are pretty expensive units, so you would want
to make sure that is what is faulty first.
#169 of 184 Re: ABS and Brake light on [carverman]
Nov 09, 2011 (10:03 am)
The scanner that was used to pull the codes I've mentioned was a fairly expensive one. It belonged to the Goodyear service center I mentioned earlier. My friend plugged into the connector under the steering wheel to retrieve them and then cleared them. Right away the code 51 came back. I just didn't have a listing of all the codes, but he did tell me what they were with a description. I was trying to write them down as he read them to me. Thanks!
#171 of 184 Re: ABS and Brake light on [cheeze74]
Nov 09, 2011 (10:17 am)
If it's showing up code 51 then the isolation solenoid and valve appear to
be sticking or faulty. Probably some corrosion from moisture in the
brake lines. This will occur over time if the brake fluid is not replaced
periodically (every 2-3 years). Time to replace it I would think.
I've never tried reading the ABS codes, because all I have is the elcheapo
OBDII code reader and it doesn't pull the codes from the ABS controller
like the more expensive shop scan tools. I'm not going to invest $2500
for a more extensive set of tests, when I rarely have an ABS fault on mine.
My only time was when the rear brake line failed this summer after 13years, and after replacing it and both wheel cylinders,
bleeding the braking entire system, it's been fine No ABS or Brake indicator.
#172 of 184 Re: ABS and Brake light on [cheeze74]
Nov 10, 2011 (11:03 am)
hey i had the same problem with the 2 lights being on, check the brake fluid, its probly low, mine said low when the lights are on, then if you have the engine on, shut it off and start it back up and the lights should turn off
#173 of 184 Re: ABS and Brake light on [acb95]
Nov 10, 2011 (11:30 am)
That's news to me. As far as I know the Dodge RWAL system does not
have a brake fluid level sensor. It uses just a compartmentalized front/rear
standard master cylinder used for many years with a dual braking system.
The ABS controller senses only two inputs. Pulses from the the VSS sensor
in the diff and a brake pressure switch located on the proportioning valve
provide input to the ABS controller (CAB)
If the rear wheels lock up, the differential is no longer turning and their
will be no pulses coming into the CAB, so it starts to initiate ABS
braking on the rear wheels for a RWAL system.
If the VSS is no longer functioning and the ignition is still on,
it may think that that is a wheel lockup if the vehicle is moving and continue with ABS. The speedometer not working or erratic would be another indication of a VSS problem.
If there is a fluid loss in the front or rear brake system, the differential
fluid pressure switch will activate and it will turn on the ABS and Brake
Lifting the battery and resetting the controller only works if there are
no faults present. If the brake pressure switch is still operated one
way or another, signifying an open brake line somewhere, the
ABS and Brake light will stay on until the braking system is repaired and
#174 of 184 Re: ABS and Brake light on [acb95]
Nov 10, 2011 (12:08 pm)
I checked the level and it is full! Don't want to overfill it.
#175 of 184 Re: ABS and Brake light on [cheeze74]
Nov 11, 2011 (12:08 am)
The level of brake fluid in master cylinder has nothing to do with your
ABS/Brake indicators being on. As long as the fluid doesn't drop down
inside the reservoir to the point that the master cylinder is sucking in air, the possible
reasons for the ABS/BRAKE light coming on..could be:
1. You have a pressure leak somewhere in one of the lines, or calipers
or wheel cylinders
2. Proportioning valve is stuck in one position?
3. VSS sensor not providing adequate pulses to the CAB. If this was the
case, the speedometer gets affected as well, since the same sensor
is used to calculate Vehicle speed by the PCM.
4. HCU (ABS pump) fault in either the isolation or dump solenoid valves.
5. ABS controller itself..although this is much lower probability.