BryanE

What would be causing my ABS Warning indicator to come on randomly on my WJ ? where would I start looking first to diagnose the issue ?

Any help would be appreciated !!

dave1123

If you can find somebody with a good multiplex scan tool like a Snap-on or similar, you can diagnose the ABS system to find out where the problem is. A bunch of times it's nothing more than the tone rings on the front axles are rusty and the sensors can't read them. These are nothing more than notched segments on the CV joint housings that look like squared off gear teeth. There are similar tone rings inside the E-brake housings on the rear axles, but they are protected from rust by being inside, although they may have brake dust collected on them. A DRB scan tool can find the problem quickly. In my case it was the ABS unit itself, so I'm just ignoring the light. I have a piece of electrical tape over the light because in my state a functioning ABS system is not required for state inspection.

You can clean off the rust on the front tone rings with a wire brush or sand blaster. It's a lot easier to do this if you pull out the front axles, but that's a chore in itself. You should check the sensors for bent mounting brackets, chafed or broken wires, or broken electrical connectors. You can bend a mounting bracket easily if you drive thru brush and get the wiring hooked on something.

BryanE

Thank you very much, That gives me a few places to start. I don't seem to be having any braking issues at the moment, So I'm hoping it just a sensor issue. I have the FSM but without the DRB Scan tool the FSM isn't much help...

CrazyMacaw

Not sure what stores are in your area but around here the Auto parts stores (Autozone, Advance Auto etc) have 'loaner' tools including scan tools you can 'borrow'.
Basically you leave a hefty deposit and when the tool is returned you get the deposit back.
Or you can just drive there and have them read the OBD/ABS codes.

BryanE

We have Autozone, NAPA & O'Reilly's Auto parts. Pretty sure they have ODB Scanner, The FSM Calls for a DRB Scan tool but at this point anything is worth a try. I could take it to the local Mopar dealer here in town but I'm pretty sure their diagnostic fees are outrageous, and they probably wouldn't tell me the exact part or part number of whatever is needed to repair it because they want to do the repair. I'll figure this out, I don't give up very easy.... Thanks for your help !!

dave1123

The last time I took my Jeep to the dealer was for a serpentine belt idler pulley that I needed fixed immediately because I was going on a trip in the morning and didn't have the time to mess with it. That's all I needed done and signed the work order to that effect. They charged me $100 diagnostic fee and when I had it out with the service manager about it, he said every vehicle that comes in gets that test! WTF? I showed him the little box where you sign that authorizes any necessary work needed to be done had been "X"ed out and I had written "Authorized for above work only." He said I needed to take it up with Corporate and I did after paying the fee to get my Jeep back. Chrysler Service Division said dealers are allowed to do that! Since then I've only bought parts at a dealer when necessary.

About the "Loaner tool" plan. Generally you pay full price for the tool and get reimbursed when you return it in good condition. Be sure to check it for condition BEFORE you leave the store with it or you could be charged for broken of missing parts.

BryanE

That's exactly why I refuse to take my Jeep to the dealer. they will F**K you every chance they get for the all mighty dollar.
As far as the tool is concerned, I know they will require a deposit and I always check the condition before leaving the store with it. Been there, Done That...lol

Thanks again Dave...!

BlueRidgeMark

Dave, you should know better. There are no "E-brake housings on the rear axles", for the simple reason that there are no E-brakes. I think the last car to be built with an emergency brake was before WWII.

The "e-brake" mentality has been responsible for a lot of accidents. Yank that thing during an emergency and you are almost certain to lose control. Can it help in some emergencies? Of course! Very rarely.

That doesn't mean that's what it's there for. It's far more likely to get you in more trouble.

It's a parking brake. It should be used every time you park your car.


The saddest part is this guy being surprised that yanking on the "e-brake" caused him to lose control.

dave1123

Well excuse my wah! PARKING brake then, okay? And everybody knows NOBODY uses the parking brake on an automatic transmission car unless you are a fanatic or a purist. I had to use it with my 62 Chrysler because the typewriter transmission at that time had no park lock. 64 had a slide lever to engage it. I have used in with every manual transmission car I've ever owned however. The funny part is in 69 GM cars, you had to have the manual transmission in reverse before you could remove the key and the clutch on the floor to start it.

Enough of this crap! All I'm saying is the tone rings for the rear ABS sensors are inside and protected so they very seldom get rusty. As long as we are on this sight seeing tour, the WJ doesn't have a speedometer gear and sensor in the t/case but instead has a sensor inside the transmission reading the notches in the park lock drum and comparing that reading with the rear wheel ABS speed sensor to detect what gear the transmission is in, thus vehicle actual speed. EVERYTHING in the WJ goes thru the PCM to be processed and then the information is sent to the gauges thru the data bus.

BlueRidgeMark

Or.... you understand the issues.

I used to have this argument with a friend of mine who was a mechanic. One day I happened to drop in on him at his shop, and he brought it up. Told me he was going to prove to me there's no need to set the parking brake on an automatic transmission because the transmission locks the wheels.

He took me over to the old-timer who did all their transmission work and asked him the question. This guy had been working on transmissions for longer than the two of us had been alive. The guy happened to have the exact transmission on the bench than my friend had in his family car. It didn't go well for my friend. The old-timer chewed him up one side and down the other for thinking thgere's no need to set the parking brake, and then he showed us in the transmission the flimsy metal tab that "locks" the transmission.

I never heard any more about it from him.

I used to be on a Ford truck forum. Told this story there, and the usual chorus of "you don't know what you're talking about" followed. Then Kovalski chimed in. He's a retired Ford transmission engineer. Told them all off, and backed me.

If you are not using your parking brake, you are doing it wrong. If you are using the term, "e-brake" or "emergency brake", you are teaching some stupid kid to think he can yank that thing in an emergency, and you just might contribute to getting some kid killed.

BryanE

BlueRidgeMark & dave1123 ,

Thank You both for your input,
I appreciate your input and advise, I claim to know enough to be dangerous. And rely on people with the experience like yourselves to keep me out of trouble. Thank You again Very much !!!

dave1123

Hey Mark! Peace?...... In all my years trying to explain to people this very thing, all I've had them do is blow me off and proceed to do it their way. This is fine because we get to put new cables in a lot of cars just because they don't use the parking brake and it's needed for state inspection. It's getting so most inspection mechanics just pretend they work and pass the vehicle anyway. New York State did a sting operation once and had to write so many citations and pull so many inspection licenses that the whole thing was just forgotten.

One of the reasons for loss of control when using the parking brake in an emergency is because usually the braking surfaces are rusty from not being used and the cables don't release quickly enough that the result is a locked rear axle. If it has been used frequently, it can be a help in an emergency if used gingerly and not abruptly.

Getting back to ABS. I find the system is not that effective because it tends to increase stopping distance while letting you retain steering control. My foot is more educated than the ABS control computer.