ASC

[FiddlerJohn]

. EXAMPLE OF THE EFFECT OF CONTROL
For example, on a slippery surface, if the vehicle tends to be under-steered contrary to the driver’s intention, a yaw moment (a rotational moment) is created to restrain the under-steering by increasing the rear-inside braking force. On the other hand, when the vehicle tends to be oversteered, a yaw moment (a restorative moment) is created to restrain the oversteering by increasing the front-outside wheel braking force. Furthermore, when it is determined that the vehicle is over-speeding, safe and stable cornering is enabled by deceleration from reducing the engine output.
. JOINT CONTROL
ASC transmits data necessary for control of ABS and TCL, performing joint control.
Control system
Control content
. ABS
Even during ABS operation, ASC performance is improved from the joint operation of the stability control.
. TCL
During acceleration, electric motor unit output is governed through joint operation with stability control.

This ECU incorporates the ABS function, EBD function, TCL function, and ASC function.
The hydraulic units of the ASC system employ the automatic pressurisation function. These systems also incorporates G and yaw rate sensor, steering wheel sensor, and master cylinder pressure sensor (integrated with hydraulic unit).
. STABILITY CONTROL DESCRIPTION
ASC-ECU detects vehicle movement based on information from various sensors and calculates a model of ideal vehicle movement. ASC-ECU compares the actual vehicle movement with the ideal vehicle model, and manages the brake of the specific wheel so that the actual vehicle movement gets close to the ideal vehicle mode. It also controls the understeer or oversteer condition by creating the yaw moment in the vehicle.

The stability control manages the vehicle attitude by creating a yaw moment from altering the balance between the cornering force and each wheel’s braking mechanism.

. TRACTION CONTROL DESCRIPTION
When the driving wheels slip on the slippery road surface, TCL applies the brake automatically, sends the signal requesting electric motor unit speed reduction to the EV-ECU, and prevents the loss of the driving force resulting from the slippage of the driving wheel.
. FAIL-SAFE AND DIAGNOSTIC FUNCTIONS
ASC-ECU constantly monitors the input and output signals. If an error is detected in the system, ASC-ECU sends a fail signal and the corresponding indicator lamp is illuminated or blinks. Various controls are processed depending on the cause of malfunction as shown below.
ASC-ECU has the following functions for easier system checks.

. Diagnosis code set
. Service data output
. Actuator test
. Freeze frame data output

. Torque Sensor, Steering Warning,
To improve operational reliability, the dual-circuit system has been adopted for the torque sensor. If any malfunction occurs in the electric power steering system, the fail-safe function of the EPS-ECU is activated, and the output current of the EPS-ECU applied to the motor is turned off. At the same time, the steering system enters manual mode, and informs a driver of the system malfunction by illuminating the warning lamp on the combination meter. The warning lamp illuminates when the following malfunctions occur: open circuit in the electric power steering system wiring harness, poor connection, malfunctions in the EPS-ECU, motor, or sensors.
Also reference:Vehicle Dynamic Behavior

. ROAD REACTION TORQUE CONTROL
By estimating the steering reaction torque from the road surface based on each wheel speed information from ASC-ECU and the steering torque information from the torque sensor installed to the steering gear assembly, and optimising the corresponding return torque to the steering neutral direction, the road reaction torque control improves the steering wheel return control at low speed and the steering feel at high speed.

. VEHICLE BEHAVIOR ESTIMATION CONTROL
By estimating the vehicle behavior during steering operation based on wheel speed information from ASC-ECU and the steering torque information from the torque sensor installed to the steering gear assembly for additional steering torque, the vehicle behavior estimation control improves the vehicle stability at medium- and high-speed steering.

 

[JoeS]

Yesterday, with a houseful of guests, I needed a quick run into town.
I live up a twisty-windy road and it had been raining…
I've lived here for >35 years and know the road, intimately.
(As an aside, somewhere I have a bunch of trophies from successful autocrossing in my past life.)
Anyway, I roared down into town, with the now-familiar ASC occasionally kicking in the juddering ABS on selective wheels. I don't like it, but it's no longer unexpected and I tolerate it.
On the climb back, cornering on what I thought was full power, the iMiEV felt gutless. Sure enough, on the next curve I glanced down at the power gauge and the needle was only halfway up despite being floored in "D"! Surmised that ASC was restricting the power.
I fumbled around and found the ASC DISABLE switch and held it for the requisite three seconds.
Mitsi came alive!
Dropped her down into "B" and had a spirited go-kartish drive home. Nicely balanced and no pesky unwanted brake application nor wimpish response.

Remember, "B" gives full power and max regen.

Conclusion:
1) I'm delighted ASC is there for my wife, who is a docile driver, anyway.
2) I'm happy that I can disable ASC for the times I'd like to wring more out of the iMiEV.

I shudder to think what various magazine road-tests will have to say about the iMiEV's higher-speed obstacle-avoidance tests. On the one hand, the ASC will keep the car in check, but on the other hand it will preclude spirited driving.

 

[sandange]

I have just experienced my first serious problem with the Miev.
Now at 44,500km ( 27,650 miles )

I took the Miev in to get it ready for our winter here in Quebec , Canada,
Installed 4 snow tires and had the anti rust oil spray treatment done at my corner garage.
When I picked it up I noted the tire wear on the summer tires was uneven,
I figured I better get an alignment done.
I picked it after garage hours with my wife giving me a lift.
I started out fine, as normal.
Then after about 1,000 feet the anti skid warning started to flash and the car lost power. I pulled over and the warning light went out,
I turned the car off then on - thought it might need a reset.
Another 1000 feet the same thing happened , this time
I turned off the ASC .
The car seems to run normally with the ASC control turned off on the back roads.
But there is no regen. I imagine the regen turns off when the ASC is tripped

Next day went back to my local garage , thought maybe the anti rust oil treatment might have gotten into a connector near one of the wheel sensors .
We lifted it up and found the sensors are located in the wheel bearing and there is no visible exposed connector.

Made an appointment with my dealer, will find out what the problem is and report back.

 

[jray3]

the anti skid warning started to flash and the car lost power. I pulled over and the warning light went out, I turned the car off then on - thought it might need a reset.

Sorry to hear this- I've experienced the same loss of power once, after a "power slide" while accelerating around a slippery corner. A quick restart did the trick, and no further issues.

 

[siai47]

There are exposed connectors but they are on the other end of the wire coming from the sensors in the hubs. The rears are plugged in to connectors located on the metal blocks that form the rear battery attachment support. I would think there would be a warning light on the dash if one of these is damaged as they are basically there to provide wheel speed data for the ABS. Is this the first time you had snow tires on the I-MiEV? If so, the front and rear tires might be a little different in size messing up the "count" from the sensors sending the ABS and ASC into a panic. You must have also reset the low tire warning system (unless using the same wheels).

 

[sandange]

No - I had the same snow tires on all last winter without a problem , They were supplied by my dealer.

I did hit a pothole and blow a front snow tire before last Christmas holidays - the rim was straighten and I had to buy a new tire - also done at the dealer.

I wonder that may have caused damage to the ASC system.

 

[sandange]

Ok
Got it figured out
Good news is our Miev is as good as the day we bought it except that it needed a wheel alignment

The cause of the problem
As it turns out, my corner garage messed up the installation of the snow tires. They mounted the wrong size tires on the wrong rims, messing up the rotation signals to the ASC.
They did get it right switching the tires to summer tire last spring, but their new mechanic made the error
Glad to have Blackie back

 

[DonDakin]

Hey Sandange,

Glad to hear that you are back on the road. This should not count as a car problem. So you are still trouble free with all those KM that you have....

Don.......

 

[sandange]

You're right , not a single problem with it to date.
Still happier than a kid in a candy store with the Miev.

I especially appreciate it after I filled up the gas tank ($80) on the Eclipse we just picked up.

 

[pbui19]

So the iMiev killed a deer last night. The darn guy just sneaked around a full size truck right in front of me, there was just no time. The surprising thing was that the iMiev just rolled over it. I think it was the left rear tow eyelet which gouged opened its belly.

Anyway, the wheel well plastic deal came clear off which I managed to save. Being less than 0.5 mile from home, i just drove home. I was lucky that the airbag didn't come on, though i was going only around 15-20mph. Then the chattering and the ASC light came on. I thought something must be loose underneath.

Fortunately we had a day-off from the rain and i managed to glue back the plastic wheel well cover and re-installed it. It's going to rain tomorrow. There was also a hole gouged out of the plastic battery cover, which i also taped up.

The test drive revealed the chattering and ASC warning and loss of power. I had checked for any loose part and didn't find any. I hadn't experience ASC engagement before so I thought there was something loose. I inspected the speed sensor, which looked fine. I diassembled the brake, thinking that may be something is loose inside, this was before i realize the chattering was the ASC. Oh, there is a bit of friction turning the wheel, the other side wheel turned a lot smoother.

I can now only drive it with ASC off. But regen is working just fine. Oh, one of the test run did showed RBS and the "!" warning.

So basically, i think i have a bad speed sensor. It looks like a simple magnetic pick up coil, I have to do a resistant check. My 2014 iMiev is now officially no longer new.

thoughts ?

Thanks

 

[databeestje]

If the wheel alignment is sufficiently out of whack that will cause a ASC to trigger too. I had that issue with a bent rear axle on a Peugeot 206 that triggered the asc on right hand turns.

 

[JoeS]

So the iMiev killed a deer last night....Oh, there is a bit of friction turning the wheel, the other side wheel turned a lot smoother....

pbui, sorry to hear about the deer - I've had many close calls myself.

That friction turning the wheel might be a clue, but, sorry, no ideas. Give me a call if you'd like to borrow a car while you're working on your i-MiEV.

 

[pbui19]

If the wheel alignment is sufficiently out of whack that will cause a ASC to trigger too. I had that issue with a bent rear axle on a Peugeot 206 that triggered the asc on right hand turns.

that's an interesting thought, I'll keep an eye out. The steering seems fine but the steering wheel neutral position is slightly offset clockwise by a few degree. It was the left side that took the deer out.

Joes: thanks for the offer, it's drivable, just without ASC.

 

[PV1]

Check your tie rods. If it knocked the steering neutral off 12 o'clock, it may have bent a tie rod.

As for the ASC, if it is continuously activating and eventually shuts off with the RBS, MCU warning light, ASC, and ASC off lights, wiring to one or more wheels is likely broken. This behavior appears when the ECU doesn't get a reading from a wheel.

 

[pbui19]

drove about 14 miles to the train station this morning. Once I was on flatland, i turned on ASC and everything worked fine, though i only got up to 40mph. So it seems that the speed sensors must be ok.

I'll check for bent rod, which shouldn't mess with the ASC right ? I think i can live with a slightly bent rod, if all it does is offset my steering wheel a bit. I like to have ASC though.

It still goes pretty straight, no apparent pulling to one side. So how would a bent rear axle cause a ASC warning ? how can i tell if an alignment is needed ?

 

[databeestje]

The ASC operates by calculating wheel speeds (in revolutions), and as such, a bent steering (front or rear) will result in differing wheel speeds for a given turning radius. The ASC will quickly realize that that math for the 4 wheel speeds doesn't match a normal corner speed and intervene on 1 or more wheels.

So yes, if you are going straight, even if the ASC is on, all tires will likely rotate the same speed unless the Toe on the front wheels is so far off that your are (literally) scrubbing the entire (front) tire off and front and rear speeds differ too much.

Get your tie rods fixed and it should just go away. Also, some of the professional damage repair services will rectify any bent A-arms and struts to get your alignment back.

Do this or you'll just write off front tires in the space of month.

 

[pbui19]

The ASC operates by calculating wheel speeds (in revolutions), and as such, a bent steering (front or rear) will result in differing wheel speeds for a given turning radius. The ASC will quickly realize that that math for the 4 wheel speeds doesn't match a normal corner speed and intervene on 1 or more wheels.

So yes, if you are going straight, even if the ASC is on, all tires will likely rotate the same speed unless the Toe on the front wheels is so far off that your are (literally) scrubbing the entire (front) tire off and front and rear speeds differ too much.

Get your tie rods fixed and it should just go away. Also, some of the professional damage repair services will rectify any bent A-arms and struts to get your alignment back.

Do this or you'll just write off front tires in the space of month.

Thanks databeestge, I guess there is more to it than just monitoring wheel speeds, since wheels speed are different during cornering. The computer must have a map of the anticipated speed variation. I also got a bunch of warning lights coming the hill last night: RBS, !, ASC ...

 

[Phximiev]

Might I suggest a visit to the dealer? And the cost of the repair may be covered under your UIM coverage?

 

[kiev]

... The steering seems fine but the steering wheel neutral position is slightly offset clockwise by a few degree. It was the left side that took the deer out.
..

i went thru a deep pothole on the left side and it caused the same steering wheel offset that you have seen. i used the string method to check wheel alignment and adjusted the tie rods to get it back straight.

 

[pbui19]

... The steering seems fine but the steering wheel neutral position is slightly offset clockwise by a few degree. It was the left side that took the deer out.
..

i went thru a deep pothole on the left side and it caused the same steering wheel offset that you have seen. i used the string method to check wheel alignment and adjusted the tie rods to get it back straight.

did you also get the RBS/car!/ASC warnings ? the angular offset is actually quite minimal. With all this rain, there has been quite a few rather deep potholes around here.

And yes, a visit to the dealer is in the plan, would the UIM warranty cover running a deer ?