Trouble Shooting help - ABS and BRAKE dash lights are on

[Black&Gifted]

Hi All:

Just replaced the two front tires on my 03 300A (no TC). Now, the ABS and BRAKE light on the dash board are illuminated. No codes are thrown (checked with my xcal2). Light goes off when the engine is off and turned over again but will come back on in a handful of miles. Thoughts on where to start the trouble shooting?

Any help is greatly appreciated.

[Blackened300a]

Check the brake fluid first.

[screamn]

Do you have stock size tires for your new fronts?

What about rear tires......stock size?

Might be speed sensor.

[Black&Gifted]

Check the brake fluid first.

Will check that in the morning. was researching a bit ago and saw that about the brake fluid as well as a the floaty. interesting thing

in my thread searching, you have helped a good number of members and have a great working knowledge in the brake/suspension/tire area. Thanks for your contributions :2thumbs:


Do you have stock size tires for your new fronts?

What about rear tires......stock size?

Might be speed sensor.

Fronts - 245/40r18 - hankook ventus v12 evo
rears - 245/55r18 - bf goodrich g-force

would this mess up the abs sensor? some threads in my search indicate this may be an issue but haven't found a conclusion yet. never thought that would through off anything...

long story short, i did replaced the front shocks a few weeks ago and haven't gotten an alignment yet as I was going to do some other suspension work soon. also, noticed my fronts were balding and figured I didn't care too much about tire wear because I'd replace them soon as well. well, had a blowout, went to small independent tire shop nearby and the front size were the only ones they had in stock. so on they went for $100 out the door.

[Blackened300a]

Will check that in the morning. was researching a bit ago and saw that about the brake fluid as well as a the floaty. interesting thing

in my thread searching, you have helped a good number of members and have a great working knowledge in the brake/suspension/tire area. Thanks for your contributions :2thumbs:


long story short, i did replaced the front shocks a few weeks ago

Glad I can help! :beer:

When the front shocks were replaced, perhaps the wire to the ABS sensor was frayed or pinched? Perhaps the sensor wasn't fully plugged in? The tire sizes mean nothing on a 300A and since you are getting a Brake light along with the ABS, I would be looking at the sensors and fluid.

[Pat]

Your XCal 2 will not scan ABS faults. Takes a special scan tool from Ford. Are your fault lites still on?

The scan tool will isolate the problem to the wheel sensors the ECU or the HCU. If a wheel sensor(s) is bad the cost is about $300.00 If the ECU is bad then the cost be will about $700.00. If the HCU is bad then the cost will also be high.

This is something that should be repaired as the ABS, Brake and T/C are all tied together. (ECU = Electronic Control Unit, not the car's main computer. The HCU is the Hydraulic Control Unit) Both of these pieces are located under the air cleaner, the HCU has several brake hard lines going in and out and the ECU is bolted to the front of it, if the ECU is replaced it may have to be programmed. The brake fluid bleeding process requires the Ford scan tool to activate each brake assembly.

I had to wait a few days for my replacement part, the ECU, to come in. The MM ECU is not re-buildable according to the companies that rebuild these things.

Also, ECUs are getting in short supply, so the dealer tech stated.

[Chevyguy]

The HCU/ECU combo was only used from 2001-2004 so no wonder parts may dry up.

[Black&Gifted]

haven't had a chance to trouble shoot much yet (car isn't my daily driver). here is what i've found out thus far:

Brake fluid was a little low and the floaty may have been stuck. Topped it off.

Brake lines look fine (except need to upgrade to SS lines), however the backside of where the abs sensor is located looks very dirty/worn. Dust shields and rotors are pretty rusty.

the lights only come on if going above 60 mph consistently for a few mile...at least that is how i've been able to replicate the fault lights going on. If she stays under 60, or only above 60 for short bursts, the lights do not go on.

[Blackened300a]

You check the ABS rings to make sure they aren't cracked or missing? Sometimes debris in the cogs will throw things off.

[Pat]

Brake lines look fine (except need to upgrade to SS lines), however the backside of where the abs sensor is located looks very dirty/worn. Dust shields and rotors are pretty rusty.

the lights only come on if going above 60 mph consistently for a few mile...at least that is how i've been able to replicate the fault lights going on. If she stays under 60, or only above 60 for short bursts, the lights do not go on.

My fault lite indications were also intermittent for a week or so, then stayed on constantly.

If you have the dealership do a diagnostic it's about $95 and they will usually deduct that from the repair cost. At least you will know what's ahead. This system is interconnected so that the ECU and HCU work together. The HCU cannot be leaking at the connection.

There is good info on the Internet under Ford ABS system.

[Richy04]

Usually the ABS will come on after you do work because debris falls and attaches itself to the sensor. The sensor is a magnetic head much like a tape recorder, it counts the pulses from the ring and brake debris, metal dust will attach itself to the sensors. Get in there with a tooth brush and gently remove the debris and it should be ok (as long as your tire sizes aren't the reason why it's tripping the light)

[KilledKenny]

The cause of your concern is that the front tires are the wrong size. The ABS module for the marauder is specifically calibrated for different size tires from the front to rear
Factory size are 235/50R18 front and 245/55 R18 rear.
The size you have in the front is 245/40 R18 which is smaller in diameter then the factory size which in turn causes the front speed sensors to read a higher MPH then expected then it turns the ABS lamp on.

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/50-18 4.6in 13.6in 27.3in 85.6in 740 0.0%
245/40-18 3.9in 12.9in 25.7in 80.8in 784 -5.6%

[Spectragod]

I had to wait a few days for my replacement part, the ECU, to come in. The MM ECU is not re-buildable according to the companies that rebuild these things.

Modulemaster says different, rebuild-able and a 5 year warranty.............notice when you buy it from Ford, they want the core, that's because it's rebuild-able.

link....................

http://www.modulemaster.com/en/index.php

[frdwrnch]

Kenny's on the ball. It's the tire size.

[71cyclone]

I Like your line up 65 67 68 04 Great "FO MO CO" LOTTO Numbers / frdwrnch

[Black&Gifted]

The cause of your concern is that the front tires are the wrong size. The ABS module for the marauder is specifically calibrated for different size tires from the front to rear
Factory size are 235/50R18 front and 245/55 R18 rear.
The size you have in the front is 245/40 R18 which is smaller in diameter then the factory size which in turn causes the front speed sensors to read a higher MPH then expected then it turns the ABS lamp on.

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/50-18 4.6in 13.6in 27.3in 85.6in 740 0.0%
245/40-18 3.9in 12.9in 25.7in 80.8in 784 -5.6%


just want to close this out and BINGO!!!!! That was the issue. Had stock fronts put on and ABS light no more!

Thank you very much to everyone who helped me trouble shoot!