'03 Hill-Start major malfunction!

[hammersmith]

Just took delivery of my new 2003 4-Runner Limited. Experiencing a
very unusual problem when attempting to drive up a slight incline
from a stop (my driveway).

On approx 15-20 degree angle, release the break and attempt to accelerate,
vehicle rolls backwards and ABS light blinks, traction control light blinks and beeps,
and engine revs held low since computer believe tires are slipping (when they are not).

Complained to dealer about this but of course after three attempts to have
repaired, they were unable to reproduce problem. After three days of getting
no where with dealer, they agreed to drive a new 4-Runner (Sport edition) to
the slight hill to compare their vehicle with mine. To our surprise, both 2003
4-Runners rolled backwards, blinked lights, and beeped.

They say since happening to both new 2003 trucks, must be the design of
the vehicle. You've got to be kidding!!! I believe I've uncovered a MAJOR
defect with the ABS/Traction Control/Hill-hold subsystem on the 2003 model.

The dealer's response is now, we just sell them we don't build them...

I'm attempting to contact someone from Toyota corporate to discuss this
critical issue but haven't had much success getting anyone to return
my calls.

Has anyone else experienced this abnormal behavior with 2003's?


PS. If you're researching new SUV's take this as a lesson. If Toyota doesn't
acknowledge this problem and issue a recall immediately, you should
not purchase a 2003 4-Runner!!!

 

[testrider]

My 2003 SR5 doesn't do this. I took this offramp everyday where it's an uphill right before a red light and I didn't notice that it ever rolled backward after I release the brake and step on the gas. Did it roll backward **right after** you released the brake? Or after you released the brake and **not** step on the gas? If you give more details how to duplicate it I'll try it on mine and let you know.

-Mike-

 

[hammersmith]

Can't hill-start

As soon as I release the break pedal the truck rolls back. Next I attempt to
accelerate and it responds like on a sheet of ice (ABS and Traction Control
systems kick in for some reason and moving forward becomes quite tricky).

On less of an incline the hill-start holds fine. However, this malfunction
is 100% reproducible in my driveway (which is on a very minor slope).

- Try coming to a complete stop on an incline.
- Still in drive, release the break pedal and try to move up the hill.
- Hang on because things get squirrelly from here!

Since it happened on two 2003's I felt it could be a design flaw.
Also, the Toyota mechanic had his hand-held computer connected to
the trucks and the diagnostics did not detect a failure.

This is clearly a problem that Toyota must fix. $43K for a truck
that can hardly make it up a 30' suburban driveway

 

[Thai]

The Hill-Assist Control (HAC) is not a definitive thing. In other words, if you're on a steep enough incline, your 4Runner WILL ROLL BACK. The system will SLOW DOWN the rolling back. It will NOT lock your wheels. It gives you a bit more time to put your foot on the gas pedal.

Of course, if you don't have HAC (before 2003) or don't want to use it, just do the "two-foot pedal method." That is, put one foot on the brake pedal and one foot on the gas pedal. Gradually let go the brake pedal and gradually press the gas pedal. It is a very common method for off-roaders.

The same method can be used when descending a hill. Therefore, for an experienced off-roader, HAC and Downhill Assist Control (DAC) are NOT needed. However, these electronic assist controls make things easier, especially for beginners.

Your 4Runner is OK. There is nothing wrong with your HAC. It is NOT a "problem" that Toyota needs to fix.

Enjoy your 4runner....

 

[Thai]

Hammersmith,

Remember, your situation will happen to ANY SUV in the world! Therefore, the Mercedes G500 or Range Rover will suffer the same "problem," and they costs around $75,000.

Also, if you use the "two-foot pedal" method, you can avoid the traction control from kicking in.

Thanks.

 

[testrider]

The Hill-Assist Control (HAC) is not a definitive thing. In other words, if you're on a steep enough incline, your 4Runner WILL ROLL BACK. The system will SLOW DOWN the rolling back. It will NOT lock your wheels. It gives you a bit more time to put your foot on the gas pedal.

Of course, if you don't have HAC (before 2003) or don't want to use it, just do the "two-foot pedal method." That is, put one foot on the brake pedal and one foot on the gas pedal. Gradually let go the brake pedal and gradually press the gas pedal. It is a very common method for off-roaders.

The same method can be used when descending a hill. Therefore, for an experienced off-roader, HAC and Downhill Assist Control (DAC) are NOT needed. However, these electronic assist controls make things easier, especially for beginners.

Your 4Runner is OK. There is nothing wrong with your HAC. It is NOT a "problem" that Toyota needs to fix.

Enjoy your 4runner....

Thai,

My understanding was like hammersmith: the hill start assist stops the truck from rolling back.
The following was from the 4Runner specs file you posted. It did say that HAC **stops** the truck.

Hillstart_Assist_SR5
----------------------------
G. Hill-start Assist Control (HAC) std on all models
1. increases stability for improved control during hill climbing
and starting & stopping on slippery surfaces
2. works to prevent vehicle rolling backwards or slipping
sideways during transition from stopped to climbing an up-slope
3. conditions:
a. always engaged: no switch;
b. transmission in any forward gear (not in Reverse);
c. any wheel rotating backwards.
4. operation:
a. HAC system will control the brakes to stop the individual
wheel or wheels and prevent the vehicle rolling
backward;
b. VSC indicator blinks & buzzer sounds;
c. brake lights illuminate when pressure is applied to any
caliper.

 

[hammersmith]

Not "OK"

According to Toyota, Hill-Start Assist Control (HAC) is designed to hold the vehicle in place for
five seconds to allow time to move your foot from the break to the accelerator. A description
of this process is covered in detail on the Toyota web site.

"Hold vehicle in place". Not, "slow it down", not "slightly creep backwards".

Forget about holding in place for a second and let's consider your suggested
"common" off-road method; one foot on the break and the other on the gas.

When I gradually release the break and gradually press the accelerator, I'm
in the same boat. Try to accelerate and the ABS and Traction control
systems kick-in. What I'm trying to say is, THE TRUCK WONT ACCELERATE and move forward
DUE TO THESE OTHER SYSTEMS INITIALIZING AND INTERFERING WITH
CONTROLLING THE VEHICLE.

Assume you're on drive pavement. Not off-road in dirt, ice, water, or banana peels-
if you believe quickly rolling backwards (using one foot or two) then trying to accelerate but having ABS
and Traction control prevent you from moving forward is "OK" then you should
trade-in that 2002 for a 2003 with all these high-tech features. (I traded in a '98
Limited w/43K miles. A huge mistake). I'd hang onto that '02 like grim death
because unless you've been behind the wheel of an '03 and experienced this
PROBLEM, you have no idea how severe it is.

My (and probably many others) '03 4Runner is very far from OK. This behavior is a major
defect that completely contradicts the design (described by Toyota).

 

[hammersmith]

Sorry Thai. I respect your opinion but you are incorrect
regarding the HAC system on the '03 and for that matter,
other vehicles with this capability.

Hill-Assist was designed for ONE purpose. To keep the vehicle
from rolling backwards and going out of control. Just read the description from Toyota. It's clear as a bell.

No "two feet", no tying the front bumper to a tree. Plain
and simple, HAC was designed to apply the breaks for you and
keep you in place on a hill! Not sure why you don't understand
this concept.

Testrider got it. Rather then a make comment such as "ANY SUV
in the world" you should at least understand HAC. You're way
off on this.

 

[Thai]

Guys, i am fully aware of what Toyota literature says. HOWEVER, the real truth to these systems is that they are NOT perfect. None of them are. If you read up on Land Rover vehicles, you will see the same complaints...and Land Rover have been incorporating these systems for years now.

Think about this...do you think the system will HOLD your 4runner if you're on a 45 degree (100%) incline?? IF it were to hold your 4Runner, how can the system know when you're gonna punch the gas?? You're talking about the brake calipers CLAMPING down on the discs and then has to act INSTANTANEOUSLY when you punch the gas pedal...what you're talking about is a system that reads your mind! If it is supposed to clamp down, then why does the ABS lights come on?????

What the system does is PULSES your brakes (thus, your ABS lights go ON)...it does NOT clamp down. If you're on a small incline, this system would work as advertise (as YOU notice). However, on more graded incline, it canNOT do it because the brakes do NOT clamp down and the force of gravity is too great for the ABS to stop your 4Runner.

Well, if you don't believe me then i guess this "problem" affects ALL 4runners. I guess you can sue Toyota for "false advertising". The system is not perfect. Toyota can update the system i guess in the near future....

Good luck.

 

[Thai]

Hammer,

"When I gradually release the break and gradually press the accelerator, I'm in the same boat. Try to accelerate and the ABS and Traction control systems kick-in."

Can you explain to me why traction control would kick in if the "two-foot pedal" method is used??? I have used it often in off-roading...don't seem to have a problem with ATRAC interfering. The whole point to GRADUALLY modulating your pedals is that your vehicle will GRADUALLY move forward, thus minimizing wheel spin. ABS is never activated by doing this method.

Thanks.

 

[Good Times]

REAL WORLD TESTED..

My driveway(cement) is approx 15% incline (one way up/ one way down) (got to use my new toys to find out the incline grade!!). And I have tested the system and I have no problems both going down and up.

Okay I've taken the new 03 out to the trails twice now.

The first time out I tested every dang feature to make sure it was working. I gotta say it works. But like what Thai said, there are limitations..

I know that going up a hill that's severely too inclined, regardless of what electronic system you have you will slide... the sheer weight of the vehicle will cause the loose rocks (ground) to make the vehicle slide... that's just pure gravity at work.

The HAC does this: Gives the driver more control. Keeping in mind that there are alot of drivers out there that do not know how to drive on the trail. This system helps to give the drive more control in going up / down hills within the vehicles limitations.

I had the HAC/DAC going down a very steep hill and all I have to say is that I heard the damn annoying beeps all the friggin way down!!! Ofcourse the computer sayin slow down cuz i'm sliding but c'mon now, the steep hill is all sandy so obviously there's going to be slipping as I decend. Now I know that if I tried stopping midway down the hill, I'd prob won't be able to stop as the decline was pretty severe... Just working the brake/pedal at the sametime going down in a controlled manner is the only way out of the bad situation.

No matter what system is on your vehicle, not everything will help. But I don't blame Toyota for this as I know that I have taken the 4runner to its upper limits. I'm just happy that I'm able to take it to that limit and enjoy the fun

Bottom line, what Thai is sayin is absolutely correct. Keep in mind that the computer can only do soo much. I personally am not too fond of the new vsc/trac/hac/dac etc etc stuff but ehe, it works for what I need it for.

If I was that anal, I would have gotten an old FJ40 to play with Atleast w/ that rig I don't have to worry about any electrical stuff as if something goes wrong, it's all me (the dang driver).

Lance

 

[Thai]

Hammer,

"tying the front bumper to a tree"...hehehe, now that i am imagining it, that's pretty funny...THAT would work great! Can you imagine someone doing that on a trail?? I would laugh my ass off!

Enjoy your 4runner.

 

[hammersmith]

Thai,

Okay, I will make one last attempt to show you why you are wrong with a video and written proof:

go to: http://toyota4runner.com/html/shop/vehicles/4runner/performance/4runner_performance.html

Play the video demo of the 4Runner climbing the hill.

From Toyota page:

Hill Start Assist Control (HAC) helps prevent the 4Runner from rolling backwards
and/or sideways when stopped on a steep incline.

As the driver switches from the break to the accelerator to resume climbing, HAC utilizes
electronic sensors within the Break Control System to detect wheel rotation.

The Runner's breaks and throttle are then gently applied, helping to avert a precarious
backward roll that can lead to wheel spin and vehicle sliding.

"Think about this...do you think the system will HOLD your 4runner if you're on a 45 degree (100%) incline?? IF it were to hold your 4Runner, how can the system know when you're gonna punch the gas?? You're talking about the brake calipers CLAMPING down on the discs and then has to act INSTANTANEOUSLY when you punch the gas pedal...what you're talking about is a system that reads your mind! If it is supposed to clamp down, then why does the ABS lights come on?????"

Now you finally understand. The system doesn't have to read your mind! The vehicle is fitted with sensors to monitor
key components (wheels, throttle, breaks, etc). You explained the exact design. Is it so difficult to grasp the concept
of sensors monitoring wheels rolling back and respond by applying breaks? Watch the Toyota video on HAC.

Read this carefully- I cannot move forward on a slight incline without ABS and Traction Control lights coming
on. No wheel spin! The system is malfunctioning. It believes the wheels are slipping so ABS and
Traction Control kick-in.


Not sure how anyone can understand or comment on this when they do not own a vehicle with HAC.
I'm not going to sue Toyota but have you every heard of a "recall"????? Stay tuned because I'll bet you a
pair of Bilstein HD shocks Toyota will issue a recall for this severe PROBLEM.

Thanks for the exchange but doesn't look like we are going to change our minds. Only thing I recommend
is watch the video and wait for news of the recall. (BTW, I'm going to look at new X5's tomorrow morning.
Local dealer has two 4.6's in stock). Sad to say but after owning four 4Runners ('88, '92, '98, '03) I'm going to move on to another manufacture).

 

[testrider]

Guys, i am fully aware of what Toyota literature says. HOWEVER, the real truth to these systems is that they are NOT perfect. None of them are. If you read up on Land Rover vehicles, you will see the same complaints...and Land Rover have been incorporating these systems for years now.

Think about this...do you think the system will HOLD your 4runner if you're on a 45 degree (100%) incline?? IF it were to hold your 4Runner, how can the system know when you're gonna punch the gas?? You're talking about the brake calipers CLAMPING down on the discs and then has to act INSTANTANEOUSLY when you punch the gas pedal...what you're talking about is a system that reads your mind! If it is supposed to clamp down, then why does the ABS lights come on?????

... snip ...

Good luck.

Thai, I'm not arguing with you here but I do like to comment on the above paragraph:

I don't know how Toyota implemented the HAC, but being an embedded software engineer myself, I would believe that it's doable: remember that the 2003 4Runner doesn't have a cable linking the gas pedal to the throttle body (it's drive-by-wire). So the brakes could clamp down when the vehicle slid backward. Then when you press on the gas pedal, because it's not linked to the throttle but rather to the computer, the computer could effectively **not ** applying **real throttle** but releasing the brakes slowly first while feeding the throttle a few milliseconds later. It's doable but again, I have no clue how Toyota implemented it.

=Mike=

 

[Good Times]

hammersmith:

I guess u didn't read my post then ehe?

This system works fine for me! And it's been trail tested by on lookers that were there...

So I dunno if it just didn't work for ya!?!

Atleast it works...

BTW a word to note.... The DAC will only work when you engage it like this:

4LO ONLY (1st gear must, Locking the center is an option) I assume you know how to get into 4LO too...

The DAC will not work on 4HI...

So if you have it in 4hi... that's prob why it won't work!!

Check to make sure it was in 4LO... and always if you're in 4LO please make sure it's not a concrete!!!

I hope that clears everything up.

Lance

 

[Good Times]

My driveway is a 15% incline.... (cement)
I'll stop 1/2 way up (brake applied). As soon as I release the brakes, the vehicle will roll back abit (1/8 turn of the wheel if that) and then it'll just sit there no problems.

Now changing the variables to a graded dirt at 15% incline, I'm pretty sure it won't be the same as the sheer weight of the vehicle will make the graded dirt slide... just gravity... it's nothing wrong w/ the system but to a certain extent, the system will not work up to what it states. The system will start beeping only because it knows the vehicle is sliding but unfortunately you really can't do much at that point as it's the ground giving away (and i think Thai was trying to point this out).

Test the system on the cement incline and see if you experience the same result. It just could be that the graded incline you encountered was beyond the limits of the weight of the vehicle on the ground. I mean the ground can only take soo much and after that whatever on it is gonna slide...

Lance

 

[Thai]

hammersmith,

First of all, control your attitude! Geez, man, have you heard of being POLITE?? You know, i am not a Toyota representative! You don't have to have a bitchy attitude towards me. You sound like my ex-girlfriend! I have been very polite towards you.

Oh yeah, the BMW X5 will be a great off-roader! I don't even think it has HAC. So, basically, you not exactly "fixing" your "problem." And BMW X5 is not known for being reliable on it's electronic stuff! Have you seen Consumer Reports on X5?? It is horrible in reliability!

I really do hope that you get your X5. It would solve your bitchy attitude. Well, at least, you will take it to a BMW forum.

I don't need to own an '03 4runner to know about HAC. I have driven an '03 4Runner and has off-roaded with Land Rovers to know about it. And, yes, I DO READ THE TOYOTA LITERATURE MANY TIMES.

BTW, Toyota is not perfect in it's literature. My '02 4runner has different height in EVERY freaking Toyota literature (brochure, internet links, website). Now, THAT is very annoying!

You still have not answered my question regarding my "two-foot pedal" method in the previous post. From my feeling, you don't know crap about off-roading.

READ THIS CAREFULLY, your 4Runner is OK. The system has LIMITATIONS. (X5 will have even more limitations!) READ GOODTIMES POST!

If you decide to get an X5, then i am happy for you. I can even recommend to you a good BMW forum, if you want.

Thanks.

 

[Thai]

Testrider,

I agree with you. Technology makes the system capable of very fast-acting responses. However, HAC and DAC work by the ABS system. If your brakes CLAMP down, then ABS lights will NOT go on. For example, if you're stop at a red light, does the ABS/Tration control light go ON?? No. The ABS system is not pulsing your brakes.

With HAC and DAC, the basic principle is pulsing your brakes, thus ABS is active, thus ABS light goes ON. (And you also hear the chattering of ABS/traction control.) If you're on a steep enough incline, it is IMPOSSIBLE for the pulsing brakes to hold your vehicle...it is against the law of nature! The ONLY way to hold your vehicle is if the brakes clamp down...and that would require you to push on the brake pedal.

DAC is also not perfect either. It does not always work on very steep inclines because your 4Runner will be going to fast downhill...faster than what the ABS system can control. In many steep inclines, you HAVE to use the two-feet method.

"Then when you press on the gas pedal, because it's not linked to the throttle but rather to the computer, the computer could effectively **not ** applying **real throttle** but releasing the brakes slowly first while feeding the throttle a few milliseconds later."

The problem with above is that your 4Runner will be really sluggish if you try to accelerate from stoplight on a small incline...then more people (aka hammersmith) will complain about how the 4runner has no power from stoplight.

The problem with most SUVs is that there must be a compromise. Too much off-road oriented, and you lose the general consumers...just look at Jeep Wrangler Rubicons. Rubi's are not selling as well as Jeep had hoped. It is too slow for the general public (slower than regular Wranglers) and rides too stiff. Every dealership in Houston area has at least two of them...which is good for my brother who is thinking of getting one. Too much on-road oriented, and you lose the respect of off-roaders...just look at Toyota Highlander or BMW X5.

Thanks.

P.S.: i do enjoy car discussion A LOT. I have no problem with making arguments...but please keep it polite.

 

[Diablo3305]

I use this system every day on the way to school, and I have never had a problem. I love this feature. I have not looked to see if the abs light comes on, I will check next time.

 

[hammersmith]

Good Times-

I read your post and I'm happy it's not happening to
your 4Runner. (Remember, I'm not having a problem
with DAC. I'm having trouble with HAC so no on/off
switch or gear selection is necessary as it is ALWAYS on).

Also, I'm not talking about a slippery surface. Just cement on
an estimated 15-20 degree incline.

Good Times, in your test you backed out of your driveway
1/2 way and stopped. As you reported, the truck moved 1/8 and
held in place. HAC working like a charm.

Now what would you think if instead of holding in place on this
very slight dry cement incline, it continued to roll back? Now rolling backwards,
what would you think if when you tried to accelerate, the truck
responded by flashing Traction Control light, flashing ABS light and
pulsing breaks thus ratcheting your FORWARD movement? What
would you think if pressing the accelerator struggled to move
your truck up your driveway?

This is what is happening to my '03 Limited and at least one of
the dealers '03 Sport's.

Let me add one more detail I neglected so far. When I leave
my house in the morning (engine only running for 15-20 seconds
or so) and back half-way down the driveway, the truck holds
in place fine. However, when I return home after driving for
20 minutes, it wont hold and the system fails. Conclusion: When
the truck is cold HAC works perfectly. When the truck is warm,
it won't hold and the unusual flashing, beeping, and clicking kick-in.
Maybe related to engine idle, or a selected microprocessor
warming.

The purpose of my post was to determine if any '03 owners
are experiencing the same PROBLEM as two local '03's.

Those of you that want to debate whether or not this is a
PROBLEM are way off course. Be happy it's not happening
to you but you must accept the fact this is a HAC malfunction
and must be addressed by Toyota.

I've tried to explain it fifty different ways but until you experience
it for yourself you have no clue what's happening. This is a
very odd problem and that's probably why no one believes it.


PLEASE READ THIS PARAGRAPH BEFORE RESPONDING!!

One last note. My dealer also didn't believe me as the truck
was in for service three days in a row. They could not reproduce
the problem at their facility so they agreed to send their chief mechanic
to my house (about 5 miles from the dealership). The mechanic
arrives at my house in a '03 Sport model. He connects his
"gameboy" (portable computer) to my warmed-up 4Runner and
experiences the PROBLEM for himself. Rolling backwards
and system lights flashing, he immediately remarks
"this is a MAJOR MALFUNCTION". Next he gets in his '03 Sport, connects
portable computer (so he can compare collected data- bad vehicle
Vs. good vehicle). To his shock, the '03 Sport also rolled back, flashed,
beeped, and ratcheted acceleration. So those of you that want to
argue if this is a PROBLEM or not- consider the fact a Toyota certified chief
mechanic says is it. Are any of you folks Toyota chief mechanics
with extensive training on '03 models?

Now for the fun part: While the dealer's top mechanic says it's
a MALFUNCTION, he goes on to tell me they can only make
repairs authorized by Toyota. If Toyota corporate does not
have a fix, the dealer cannot do a thing. Also, the dealers
service manager had the nerve to say since it's happening
to both '03's, must be part of the design therefore why try
to fix it? But what about it working when the truck is cold
then failing when warm??? Hello. McFly!

I asked him if he believed when the Firestone tires started
coming apart and killing drivers, since it was happening to
multiple tires, must be the intended design so no need to
have Firestone investigate and correct?

Dealer went on to say "we just sell and service, we don't
design and build 'em".

I opened a call with Toyota Corporate. According to the
dealer, the fix must originate from them.

Will keep all posted of the results. But for heaven's sake,
enough with the explainations of DAC/HAC and "it's not broke" posts! Let it go. (Look, I loved Toyota. I've owned FOUR
brand new top-of-the-line 4Runners!!! But this new puppy
is sick and needs a cure).

It is BROKE and hopefully you'll see the light soon (in the
form of a recall).