On two occasions last summer my wife had the ABS engage in non emergency braking situations. She was stopping normally and the brake pedal became very hard to engage (hard to press) and she states that with extreme pressure the ABS engaged and she was able to stop. No warning lights activated on the dash. Both occasions the temp was very high with high humidity. Figure 90+ temp which is on the extreme high side for us in Maine. The problem has NOT reoccurred, but as summer and high heat approach I am trying to narrow the issue in the event that it is related to high heat/humidity situations. Before I buy and have installed a new Master Cylinder Assembly has anyone encountered a similar problem and an alternate remedy? I have not had a thorough inspection done on the brakes themselves which would probably be a good first step. Without a warning light would there be any error codes to check?
ABS Engaging 99 LC (1 Viewer)
- Thread starter mainecruiser
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Trunk Monkey
Moderator
I wouldn't throw money at a new MC for a problem that's happened once and may not even be related. Check the ABS sensors, they may need to be cleaned.
Personally, after speaking with my mechanic and having a similar problem, I just had my ABS disabled altogether. Been driving for 3 years without it, and never felt "in danger" or anything because of it. This may not be the best route for you, but for me it seemed to be (and the most cost effective). Also I live in Florida, and it gets some kinda hot down here, and that's when it started to give me issues.
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Not thinking that's the best decision. You have a 3 ton vehicle with an un-diagnosed braking problem and your solution was to disable a primary safety feature. If it's a 00+ (OP was 99 so doesn't apply), you've also now disabled VSC and ATRAC.
Regarding the heat, these things were build to withstand desert and outback so I'm not thinking heat should be the sole cause.
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Great question - from the ABS Warning Light Circuit section of the FSM, this excerpt taken literally sounds like the light would go on if a DTC (Diagnostic Trouble Code) were recorded
"If the ECU detects trouble, it lights the ABS warning light while at the same time prohibiting ABS control. At
this time, the ECU records a DTC in memory."
However, as an example, it's also possible that the warning light itself is dead or not functional. If you're comfortable trying to diagnose it yourself there are detailed steps in the FSM. If you're most concernced about safety and fixing it quickly I would take it to a shop to look at.
Note - an obd scanner will not show you the ABS DTCs - you either need Techstream, a handheld tester, or you can use the steps in the FSM under "In case of not using TOYOTA hand−held tester".
Here's how to get the DTCs (out of the '99 FSM):
PRE−CHECK
1. DIAGNOSIS SYSTEM
(a) Check the warning lights and buzzer.
(1) Release parking brake lever.
(2) When the ignition switch is turned ON, check that
the ABS warning lights go on for 3 seconds.
(3) Check the BRAKE warning light lights up when the
ignition switch is turned ON and the light goes off
when the engine starts.
(4) When 120 seconds have elapsed after the ignition
switch was turned ON, depressing and releasing
the brake pedal continuously with full stroke 15 − 20
times within 10 sec. Warning light lights up and
buzzer sounds.
HINT:
If the indicator check result is not normal, proceed to troubleshooting
for the ABS warning light circuit (See page DI−294).
(b) In case of not using TOYOTA hand−held tester:
Check the DTC.
(1) Disconnect the short pin from DLC1.
(2) Using SST, connect terminals Tc and E1 of DLC1.
SST 09843−18020
(3) Turn the ignition switch ON.
(4) Read the DTC from the ABS warning light on the
combination meter.
HINT:
If no code appears, inspect the diagnostic circuit or ABS
warning light circuit (See page DI−294 or DI−303).
As an example, the blinking patterns for normal code and
codes 11 and 21 are shown on the left.
(5) Codes are explained in the code table on page
DI−225.
(6) After completing the check, disconnect terminals Tc
and E1, and turn off the display.
If 2 or more malfunctions are indicated at the same time the lowest
numbered DTC will be displayed 1st.
(c) In case of using TOYOTA hand−held tester:
Check the DTC.
(1) Hook up the TOYOTA hand−held tester to the
DLC3.
(2) Read the DTC by following the prompts on the tester
screen.
HINT:
Please refer to the TOYOTA hand−held tester operator’s manual
for further details.
(d) In case of not using TOYOTA hand−held tester:
Clear the DTC.
(1) Using SST, connect terminals Tc and E1 of DLC1
and remove the short pin from DLC1.
SST 09843−18020
(2) Turn the ignition switch ON.
(3) Clear the DTC stored in ECU by depressing the
brake pedal 8 or more times within 5 seconds.
(4) Check that the warning light shows the normal
code.
(5) Remove the SST from the terminals of DLC1.
SST 09843−18020
(6) Connect the short pin to DLC1.
HINT:
Disconnecting the battery cable during repairs will not erase the
DTC in the ECU.
(e) In case of using TOYOTA hand−held tester:
Clear the DTC.
(1) Hook up the TOYOTA hand−held tester to the
DLC3.
(2) Turn the ignition switch ON.
(3) Operate the TOYOTA hand−held tester to erase the
codes.
(See TOYOTA hand−held tester operator’s manual.)
(f) (Reference):
Using TOYOTA break−out−box and TOYOTA hand−held
tester, measure the ECU terminal values.
(1) Turn the ignition switch OFF.
(2) Hook up the TOYOTA break−out−box and TOYOTA
hand−held tester to the vehicle.
(3) Turn the ignition switch ON.
(4) Read the ECU input/output values by following the
prompts on the tester screen.
HINT:
TOYOTA hand−held tester has a ”Snapshot” function.
This records the measured values and is effective in the
diagnosis of intermittent problems.
Please refer to the TOYOTA hand−held tester/TOYOTA
break−out−box operator’s manual for further details.
ABS sensors are purely electronic; they pick up pulses at the hub. I would think you'd get an ABS light on the dash if a sensor went out.
Moisture in brake fluid is always a bad thing and necessitates routine maintenance (flushing). A low-cost fix attempt would be to have a Toyota dealer perform a flush using their computer to cycle valves and pumps, ensuring all fluid is exchanged.
Trunk Monkey
Moderator
The ABS sensors are magnetic. They can pick up all the tiny bits of metal floating around in the hub and off the brakes in the rear. Mine would activate momentarily coming to a slow stop, just before stopping. Wiped them off, good to go.
Yeah, I was very weary and first, but I was assured by my very trusted mechanic and several other "truck/car savy" guys I know that it would be ok. Brakes work great still. They have locked up on me once in three years. It was one night when a guy ran a stop light in front of me while it was raining. Brakes locked as I came within a foot of the guy while I was fish tailing. Recovered just fine, and kept on truckin down the road. I dunno if ABS would have helped there or not, never had it kick in while I had it. Gotta love my Land Cruiser though, totally saved my life in that situation.
Mine is a 99, as is his, so no worries about disabling everything.
Mine is a 99, as is his, so no worries about disabling everything.
- Thread starter
- #11
I just want to be sure I am not making a 2K investment in the repair before I know it’s necessary. Clearly there have been some issues with these systems, just want to investigate all possible avenues before proceeding. Not big on disconnecting the ABS, but an option to consider. I think I will proceed with other recommendations (clean sensor, change fluid and check for any ABS DTC’s) first before going the MCA route.
Thanks for the advice, I’ll report back with any pertinent findings.
Thanks for the advice, I’ll report back with any pertinent findings.
and then next time when you're trying to brake and avoid, or brake while in a corner? ABS is as much for preserving directional control as it is in minimizing stopping distance.
are you prepared to tell a jury some day how your 'expert mechanic' is smarter than toyota engineers (not to mention a DOT requirement for ABS on SUVs that started in 1999)?
I meant disabling VSC and ATRAC...which a 99 doesn't have...
And I really don't want to start an argument even though you really seem to want to pick one. I'll just let it all go, and stick to the concept that we are in a Tech Forum.
Test everything you can on your own, then take it in to get it diagnosed would be the best idea. It can be a very expensive repair, but if my (future) wife were to be driving often, I'd do everything I could to have her in a safe vehicle
And I really don't want to start an argument even though you really seem to want to pick one. I'll just let it all go, and stick to the concept that we are in a Tech Forum.
Test everything you can on your own, then take it in to get it diagnosed would be the best idea. It can be a very expensive repair, but if my (future) wife were to be driving often, I'd do everything I could to have her in a safe vehicle
I just picked up an 04. With any luck, I will have my ABS disabled as well. According to the PO, the ABS is why it wanted to take a nap on its roof at 10 MPH.
My 98 4runner, 96 LC are both disabled and also every other toyota I have owned with ABS. TOYOTA's ABS in the trucks, cruisers and 4runners from its beginning has been piss poor.
The purists who cry about the ABS and don't disable it because you will kill a bus load of nuns, likely have never had the ABS try and think for you on a slippery road trying to stop and put you into the ditch.
My 98 4runner, 96 LC are both disabled and also every other toyota I have owned with ABS. TOYOTA's ABS in the trucks, cruisers and 4runners from its beginning has been piss poor.
The purists who cry about the ABS and don't disable it because you will kill a bus load of nuns, likely have never had the ABS try and think for you on a slippery road trying to stop and put you into the ditch.
Nothing is perfect and there will always be stories of guys who blame their mistakes on ABS. I'm sure there are a *few* legitimate cases of ABS intervention making things worse. But for every one of these there are 100's or 1000's of ABS saves every day, you just don't hear about it because it works so well and most folks don't even notice it. The data is really irrefutable and is backed by real cost savings by the insurance companies. Do you really think they mandate it because it makes things worse? Or is there something special about your driving skills that make you exempt from the statistics?
My point, by the way, is regarding daily driving on the road. If you're talking strictly off-road then I would agree that ABS can get in the way *sometimes* on loose surfaces. Even then, I wouldn't disable it on a 00+ or newer 100 as you'll lose ATRAC.
I for one would be really pissed if someone hit me because they disabled a safety feature on their vehicle under the premise they could drive better than the electronics in an emergency situation. You're also running the risk of your insurance voiding a claim not to mention criminal and civil charges.
My point, by the way, is regarding daily driving on the road. If you're talking strictly off-road then I would agree that ABS can get in the way *sometimes* on loose surfaces. Even then, I wouldn't disable it on a 00+ or newer 100 as you'll lose ATRAC.
I for one would be really pissed if someone hit me because they disabled a safety feature on their vehicle under the premise they could drive better than the electronics in an emergency situation. You're also running the risk of your insurance voiding a claim not to mention criminal and civil charges.
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never had ABS issue on FJC or 100....so dont know what everyone is talking about. I have seen people that ride the brake cause ABS to come on while going slow...if it detects even momentary pedal input that lets off and quickly goes back on...then it will activate.
Both of these are probably new enough where they got the abs figured out and it works. I should mention my 02 tundra the ABS never acted up on me and seemed to work great in the winter. I guess I should of noted most of my rigs have been below the year 1997... Ha..
Main problem i have encountered (FJ80 and 4runners and mini trucks)'s is you hit the brakes on something slippery (on road, ice or snow, trying to stop at the stop sign), the abs engages, starts pulsating, you let of the brake and there is about a 5 second delay where it keeps doing it. Or I have had the fronts completely engage without touching the brakes at all. Had to pull the abs fuse for them to "unlock". I've owned 8 - 80's and every one has had an issue (7 where identical the pulsating) and I am not the only person who agrees the 80's abs system sucks ass. Again, this is 80 experience not a 100.
I am sure if you are in an accident, the last thing on your mind is going to be, I wonder if his ABS was up to par....
When I hit the bus full of nuns and they see my abs fuse is pulled, they can take me to court.
Both of these are probably new enough where they got the abs figured out and it works. I should mention my 02 tundra the ABS never acted up on me and seemed to work great in the winter. I guess I should of noted most of my rigs have been below the year 1997... Ha..
Main problem i have encountered (FJ80)'s is you hit the brakes on something slippery (on road, ice or snow, trying to stop at the stop sign), the abs engages, starts pulsating, you let of the brake and there is about a 5 second delay where it keeps doing it. Or I have had the fronts completely engage without touching the brakes at all. Had to pull the abs fuse for them to "unlock". I've owned 8 - 80's and every one has had an issue and I am not the only person who agrees the 80's abs system sucks ass. Again, this is 80 experience not a 100.
I am sure if you are in an accident, the last thing on your mind is going to be, I wonder if his ABS was up to par....
When I hit the bus full of nuns and they see my abs fuse is pulled, they can take me to court.
APKhaos
Unfixing the unfixable
My ABS is down with a solid ABS light. All other brake ops are normal.
Going to try reading the DTCs based on the procedure that agaisin posted above. Anyone have a list of the ABS system codes?
Also, I've been relying on AllData for tech info which is a constant frustration. Anyone have a good source for shop manuals? Nothing on eBay, but I'll keep looking there as well.
Going to try reading the DTCs based on the procedure that agaisin posted above. Anyone have a list of the ABS system codes?
Also, I've been relying on AllData for tech info which is a constant frustration. Anyone have a good source for shop manuals? Nothing on eBay, but I'll keep looking there as well.
APKhaos
Unfixing the unfixable
OK, Found the 2004 service manual. Search IS your friend, after all 
