Abs false engagement

Aaron

New LVC Member
Joined
Jun 17, 2017
Messages
2
Reaction score
0
Location
North Carolina
I have a 2000 lincoln ls with 56,000 miles on it. I replaced front hubs due to wheel bearing roaring. Now when going down road at low speeds the abs is kicking in on its own and also when i brake. Its the drivers side thats doing it. When i unplug the hub it dont do it. I replaced the hub 2 times and even put old one back on just to see if it does it and it does. Didnt have this issue before hand. Abs light does not come on when it happens nor does the traction control light.Also from time to time the parking brake light comes on for a few then goes off. Dont know if its related to the issue. Anybody have any ideas? Car drives great.
 
Double check the wiring/connector to and the LF wheel speed sensor itself.
Inspect for cracks/damage. Ensure connector is fully seated.

Really need a scan tool that is ABS capable to proper diagnose.
Need to be able to read the DTC's to determine root cause.

Your issue should be right at 20mph
 
My buddy gonna scan it whenever i can get up with him. I have checked the harness for cracks and made sure it fully seats. I thought bout that soon as it started.
 
Bumping this thread because I am now experiencing this same problem - although I think my problem is in the rear sensors, since my front hubs were recently replaced. (will check fronts out anyway). Figured I would post here to see if I can get any additional thoughts or diagnosis guidance before I check this out over the weekend.

Symptoms:
Seems like braking at speeds below 35 or around slow corners, especially on uneven pavement/bumps will trigger the ABS. I get the pedal sensation and can hear the solenoids going like crazy. It is kind of scary because it catches you off guard and the car does react to it a bit.

I get a flashing advancetrak light, and "check advance trak" on the message center shortly after each incident. I cannot seem to locate my scan tool. Message goes away after the car is turned off/turned back on. Assuming it is stored in there, otherwise ill have to wait for the next time it occurs.
 
This sounds like a different problem.
Does it do it if you disable AdvanceTrac? If not, it might be the yaw or steering angle sensor instead. It could also be a very bad alignment (steering way off center).
 
Yes - it occurs with AT set to off
Alignment is fresh (just had it done, and the car drives well in that regard)

**Side note though, my return to center has been bad for a while, regardless of caster and alignment.** Is the YAW module what is mounted right under the console? Since I have no interior panels, I have been wondering what that little box is.
 
...**Side note though, my return to center has been bad for a while, regardless of caster and alignment.** Is the YAW module what is mounted right under the console? Since I have no interior panels, I have been wondering what that little box is.

Yes, that's the yaw sensor. I wonder if the center return problem is related? Did you check the intermediate shaft u-joints?
 
I have not yet done so - do I need a helper to move the wheel while I watch?
 
I have not yet done so - do I need a helper to move the wheel while I watch?

I'm not sure if you can tell much by watching them. May have to remove the intermediate shaft and rotate the joints by hand.
 
Going to look at the car tonight, anything else I should check other than scanning the car with the tool?
 
Going to look at the car tonight, anything else I should check other than scanning the car with the tool?

If you don't get any related codes, then monitor each wheel speed sensor, steering angle sensor and the yaw sensor while driving and triggering the problem. You may not be able to do them all at the same time.
 
Joe, Can I do the monitoring with Forscan? I am getting my elm227 back this weekend so I will do more diagnostics then. For what its worth, the false engagement occurred when turning and braking simultaneously, (or shortly after turning) for both R and L directions.

I am trying to understand why I should be looking into steering - Are you suggesting if the steering is slow to return or otherwise defective, there may be a difference in what the angle sensors sees vs where the wheels actually are, causing the system to initiate ABS because it thinks something is going wrong?

Update:
I did manage to get the wheels off last night and can confirm visually all 4 sensors look "fine". I also looked at the intermediate shaft, but I don't know what I am looking for there
 
Yes, Forscan should do that.
My thought is that since it is when turning, the steering angle and yaw sensor indications might not be matching.
I think that you would have to take the intermediate shaft off and rotate it by hand to see if the u-joints are the problem. Short of that, spraying some lube on them and checking to see if there is some improvement in the steering could tell you something too.
 
Ok got it, thanks

Am I looking for excessive play? Loose Bolts?

I am assuming this can be done from the bottom, does not look to be enough room from the top with the head and booster in the way.
 
Basically, it would be the u-joint(s) locking up* at certain positions. *: Locking up meaning in this case that it suddenly needs more effort to continue moving it in that direction.

You can get to it to spray it from under the car. It's not impossible from under the hood. To remove it, you have to get under the dash, and under the car.

2006 Lincoln LS Workshop Manual
 
Got the intermediate shaft out last night (pretty easy to do, I was surprised).

U-Joints spun easily/freely. I do not suspect this being my new ABS issue, nor my delayed return to center. I let the IS sit in penetrating lube overnight regardless, figured while its out it cannot hurt. Will reinstall tonight and try logging the car for when the next event happens.
 
Update - I don't drive the car often, so i started to this week every day, now that I have the ELM227 and forscan back in my possession to try and get more info on this issue.

Finally, today (day 4 of driving it) the issue occurred. This time it was again at low speed, but I could hear clicking from the rear right (Near battery - I have a gutted interior so noises are louder than normal) and then shortly after that the brakes/ABS engaged. After I got off the brake, and drove away they engaged again (not on brakes at all, but when accelerating), but i was still turning out of a driveway. (steering not straight). It happened with advance trak switched on. Every time this happens, the engagement is very intermittent. The pedal pulse like normal ABS engagement, but it is very on and off, not constant on, constant off. It kinda cycles a few times over the course of each stop the car makes. Also, this seems to only occur at 10mph or less (thank god)

Forscan shows the following codes in the ABS module:
C1278 Steering Wheel Angle 1 and 2 Signal Fault
U1073 Engine Coolant Temp Sensor
U1262 SCP Data Link Fault
C1805 Mismatched PCM
B2900 VIN Mismatch

(No idea about those last two, and Forscan suggest the "U" codes aren't always problem indicators. So I am focusing on the first right now)

Guidance from the Scan app:
"This code is set when the calculated steering wheel angle is greater than 15 degrees while the steering is in the straight ahead position.

This may be caused by:
Misalignment of steering system
insecurely mounted sensor
Excessive wear in the steering system"

Any idea on where to start diagnosing next?
 
The steering angle sensor seems to be optical. Maybe you could try cleaning it? I think that you'd have to take the column out (not as bad as it sounds) to get to it to take it apart and wipe the optics. Given that, maybe start by hitting it with some compressed air without taking anything out/apart. If it makes some difference, then it would indicate you are looking in the right place.
Otherwise, you could take the center column off and look and see if the yaw sensor is bolted down tight. (Gen II you only have to pull the cup holder section up.)
 
Center console is out of the car, so I see the Yaw sensor every day, and it is nice and tight to the body.

I had the column and wheel off when I pulled the dash off to remove heatercore, so I will start with your suggestion on blowing it or cleaning it. Does anyone still sell the sensor new? Fordpartsgiant is showing discontinued, I will check tasca and a few others in case it comes to that.
 
Am I looking for excessive play? Loose Bolts?

I'm going to assume you're driving this car aggresively. Check the bolts where the steering rack attaches to the subframe and torque as necessary.

A while back I noticed my LS seemed to be plowing slightly through corners, and on a straight section of road it would want to wander... making me constantly correct it, (strong crosswinds were a total beotch). It also seemed to have a minor issue with RTC.

Torquing down the rack bolts made it feel like a new vehicle, and all the symptoms have gone away, (other than needing a caster adjustment) .


Guidance from the Scan app:
"This code is set when the calculated steering wheel angle is greater than 15 degrees while the steering is in the straight ahead position.

Loose rack bolts could cause this.
 
Am I looking for excessive play? Loose Bolts?

I'm going to assume you're driving this car aggresively. Check the bolts where the steering rack attaches to the subframe and torque as necessary.

A while back I noticed my LS seemed to be plowing slightly through corners, and on a straight section of road it would want to wander... making me constantly correct it, (strong crosswinds were a total beotch). It also seemed to have a minor issue with RTC.

Torquing down the rack bolts made it feel like a new vehicle, and all the symptoms have gone away, (other than needing a caster adjustment) .


Guidance from the Scan app:
"This code is set when the calculated steering wheel angle is greater than 15 degrees while the steering is in the straight ahead position.

Loose rack bolts could cause this.
 

Members online

No members online now.
Back
Top