Questions about ESC

[sherrod]

I'm trying to better understand the operation of the Electronic Stability Control (ESC) system. I know that its basic function is to perform throttle control and differential braking to keep the car from sliding, but I don't understand the details.

I have seen a number of messages in this forum where Genesis owners complain about ESC being a "nanny" that won't let them drive the way they want. I guess I'm not as aggressive a driver as others, but I've never had ESC engage during normal operations.

Once I decided to test ESC, so on a rainy day I floored it while turning sharp right from a stop. The white ESC light on the instrument panel flashed on, and apparently the throttle was reduced, because I didn't hear any tire squeal. But other than not having any skidding, I didn't notice any effect on the handling of the car. If I hadn't been looking for the ESC light, I wouldn't have known it engaged. Its actions certainly weren’t something I would complain about.

I believe ESC is triggered by two things:

1. It detects drive wheel skidding and reduces the power to stop it.

2. Gyroscopic sensors detect the car is spinning (i.e., rate of turn is greater than expected for steering wheel angle), and differential braking is applied to correct for the spin. I don't know if the throttle is also reduced in this situation.

Am I correct about the triggering events and resulting actions?

Under what situations have you found ESC problematic?

 

[nearwater]

I haven't driven my Genesis in the snow, so I'm not sure how it'll react to slippery conditions.
During normal driving on dry pavements, the ESC activates when I make an agressive turn but I never found it intruding to be considered as a problem.

Dan

 

[RonP]

If your driving in the snow, without snow tires, the light will flash a lot.

 

[sherrod]

If your driving in the snow, without snow tires, the light will flash a lot.

That's a good thing, right?

 

[CanukV6]

I'm trying to better understand the operation of the Electronic Stability Control (ESC) system. I know that its basic function is to perform throttle control and differential braking to keep the car from sliding, but I don't understand the details.

I have seen a number of messages in this forum where Genesis owners complain about ESC being a "nanny" that won't let them drive the way they want. I guess I'm not as aggressive a driver as others, but I've never had ESC engage during normal operations.

I believe ESC is triggered by two things:

1. It detects drive wheel skidding and reduces the power to stop it.

2. Gyroscopic sensors detect the car is spinning (i.e., rate of turn is greater than expected for steering wheel angle), and differential braking is applied to correct for the spin. I don't know if the throttle is also reduced in this situation.

Am I correct about the triggering events and resulting actions?

Under what situations have you found ESC problematic?

You are basically correct about how the ESC system works.

First it uses the ABS sensors to detect a speed differential between a rear wheel or wheels and the front wheels. if it detects a large difference it assumes the wheel is slipping and applies the brake to that wheel or wheels until it matches the front wheel speed. If the speed difference continues, it will then reduce the power by cutting back on the engine rpm.

There are also "Yaw Sensors" that detect the attitude and motion of the car and compare the signals to the position of the steering and road speed to determine if the car is merely turning (as in around a corner) or sliding. If it thinks the car is sliding then it will brake the inside (usually rear) wheel or wheels to try and correct the slide and most times will also reduce engine power at the same time.

All the above is with the ESC system switched on. If you turn it off, it will allow some wheel slippage and a higher degree of slide but will still intervene if it thinks you are getting too far out of shape. To those that want to do some controlled powersliding the ESC is a hinderance and for a skilled driver it does intervene too early and too aggressively.

 

[Disaster]

I
I have seen a number of messages in this forum where Genesis owners complain about ESC being a "nanny" that won't let them drive the way they want. I guess I'm not as aggressive a driver as others, but I've never had ESC engage during normal operations.

Once I decided to test ESC, so on a rainy day I floored it while turning sharp right from a stop. The white ESC light on the instrument panel flashed on, and apparently the throttle was reduced, because I didn't hear any tire squeal. But other than not having any skidding, I didn't notice any effect on the handling of the car. If I hadn't been looking for the ESC light, I wouldn't have known it engaged. Its actions certainly weren’t something I would complain about.

Under normal conditions, on dry pavement, keeping the wheels from spinning is the fastest way to go. On lose surfaces, like dirt, gravel or a thick snow, it is faster to drift the tail a bit.

But, even on surfaces where you want to keep traction, the ESC has a tendency to act late and aggressively, as opposed to early and more smoothly. It will allow the car to get loose, than clamp down hard on the throttle. The rule of smooth is fast is exacerbated with the ESC and traction control.

In some cases the thing that is supposed to make you safer can actually endangers you. Once, in snowy conditions, I pulled out of a side street and turned left. I didn't realize how fast the car to my left was coming at me. My instantaneous reaction was to nail the throttle. Without ESC this would have kicked the rear end out, and I would have power slid into the other lane and been safely on my way as he passed by me. What happened instead was the ESC kicked in high gear and cut the power to what felt like 10 horsepower and I creeeeeepppped across the road as the oncoming driver bore down on me, horn a'blazing. Instead of being safely out of the way I barely made it out of his way as he screamed by...inches from my rear fender.

 

[ASHDUMP]

I pulled out of a sub shop the other day trying to get across a busy rt6 and must have hit a patch of sand. The esc kicked on and definitely limited me from getting across the 2 lanes quickly. It would have been better if it didn't go on thats for sure.

 

[2ez24get]

In states where emission testing is done the rear ABS is disconnected. The Factory shop manual says the TCS is limited if one of the abs sensors is disconnected. This may work for disabling the TCS and allowing the speedo to work.

 

[ctrcbob]

In states where emission testing is done the rear ABS is disconnected. The Factory shop manual says the TCS is limited if one of the abs sensors is disconnected. This may work for disabling the TCS and allowing the speedo to work.

I'm not an authority on emission testing, so tell me why would they disconnect the rear ABS (if such a thing can really be done) when doing emission testing? Why disable the TCS on the 4.6 which has TCS? Why fool with the ESC at all? As far as I know, when testing, they put the car on rollers, with the car in gear and engine running.

 

[2ez24get]

The ABS Speed sensors control the TCS. To temporarly disable the TCS they will disconnect one or both sensors before running the car on the rollers. If they did not the car TCS would kickin and apply rear wheel braking and engine management as the front wheels are not moving but the rear wheels are.

______________________________

Help support this site so it can continue supporting you!

 

[ctrcbob]

OK. Understood. (What a PITA, this emission testing)