I tried posting this on the V10 forum with no luck. Figured I'd try here.

I have an 2000 E450 (might be a '99 frame) with a class C motorhome attached. This thing gets little use, about 1000 miles a year. It was last driven about 4 months ago. It has a total of 34K.
When I started it today, the brake & ABS light are on and stay on. The pedal is a little spongy (if I hold steady firm pressure, it will creep to the floor). When I start the engine, the lights are on for the normal light check time...then they go out for a split second, then they come back on. This is a new problem as everything was fine when parked, and now the brakes seem to work, just problems as described.
I have tried pulling the fuses, as was suggested elsewhere in this forum...That didn't work. I also topped off the fluid and also made sure the power steering fluid was full (hydro boost), that also didn't help.
I have found the connector for a brake code reader (2 wire) however I don't know if I can pull the codes via the warning light, or if I actually need a reader.

All suggestions will be welcome. I do understand this stuff....all except the ABS parts (they didn't have that stuff when I stopped turning wrenches).

Thanks for your input.

Bill the nube.

As an electrician I always suggest:
"Its only a shock if you don't expect it"

 

I'd look to see if your covered under the brake sensor recall/TSB from a few years back. The sensor could be leaking/failed. I am not very good with the diesel, but the ABS module should talk to the GEM and ECM, all should communicate with OBD2 port if you have one. Which means that you need a very specialized reader, and at $500 for just the hardware, it's usually worth giving the dealer $100 to test the communication.

 

Welcome to FTE Bill. Quick question for you. What motor do you have? You mentioned posting in the V-10 section, but also mention the hydro-boost (diesel) brakes. The gas motors have a recall for part of the cruise control system (sensor mounted on master cylinder), the diesels can't do the dash light flashing tests.

 

if your pedel sinks to the floor i would be looking for leaks, or thinking of replacing master cylender

kenny

 

Hey, Bill...

Crawl under there and check the resistance of the rear differential ABS sensor. It's a common failure on these chassis and may cause your set of warning lamps when it opens.

Top of differential.

Steve

 

yes it could be the rear vss sensor, but i would fix the brakes first if it were me

one step at a time gang
ken

 

The system probably needs bleeding to get air out of it. However, that won't be the cause of the fault lights.

BTW, a faulty fluid level switch will also cause the same warning lights...

Steve

 

or low fluid would also cause the light.

However to me personally, i would rather see the light all day long and have my brakes not creep to the floor then to have the light be out and have brakes that creep to the floor... maybe im crazy?

kenny

 

Not a bit. Both issues need to be addressed and I'm with you on the hydraulics as the higher priority. Since my specialty is electronics, I had focused on it first...

Steve

 

can anyone tell me if the system that billclou is talking about is full ABS or the Kelsey Hayes RABS? If it is the RABS then both lights on together is usually caused by loose/dirty electrical connections at the master cylinder. The sinking brake pedal could be caused by a faulty RABS valve body solenoid valve.

 

The brake ABS seems to be 4 wheel as there are sensors on the front calipers. Yesterday, I pulled the brake fluid sensor connection and it was quite clean. I don't, however, have a pinout schematic for me to be able to check the switch, or bypass it in the plug (3 wires???).
I did find a mechanic that is willing to read the codes ($70) as long as I bring the rig in in the late afternoon.....like in about 3.5 hours. I'm not sure if he will want to do the repairs or not......He may just point me in the right direction.

Thanks for all the input.............I'll keep you posted.

Bill


As an electrician I always suggest:
"Its only a shock if you don't expect it"

 

Well, just got back from the mechanic. It appears that the rear VSS is out. I kinda discounted that as a problem as my spedo is working fine...........should have looked for the spedo cable to the trans.
This new (to me) mechanic found the problem, so I'll let him fix it. In this economy we all need the work.

Thanks to all
Bill

As an electrician I always suggest:
"Its only a shock if you don't expect it"

 

i have tested this on my truck and if i remember right I had the rear vss completely disconnected and it still read speed because it was getting the signal from the front wheels

I have a 2003 F250 with a 5.4

kenny