I own a 2005 Honda CR-V. The vehicle has the Vehicle Stability Assistance (VSA) feature. It started acting up on a trip, and at times, it would not allow me to accelerate to highway speed. Sometimes, I could not go above 40mph. If I tried, the car stuttered with a multiple, quick jolts. The kids said the car had hiccups. Oddly, this bizarre behaviors only manifested on the straight-aways when VSA is designed for better control on curves, as I understand it.
My question is: I need to know if other SUVs have VSA? My friend works on Fords. Would he know about how VSA systems work? Is this Honda-specific, or perhaps there is a generic name for this system?
Yes, other SUVs have stability control but the systems are probably different between manufacturers. Maybe you’ll get lucky and we have a Honda mechanic Doper, or maybe one of the other mechanics here might be able to speak generally about stability control systems. Otherwise, it would be wise to track down a Honda message board and post about your problem there. There is a good chance that other owners have had the same problem and there might be folks who are familiar with Honda’s system.
I don’t have a Honda but both my vehicles have buttons to deactivate stability control. Have you tried that?
Dumb question from a non-mechanic, but why do you assume that the acceleration issue was due to the vehicle stability control system? My first thought (again, not a mechanic here) would have been that there was a problem with the transmission.
Yes, I tried to no avail. Once you get an error message regarding the VSA, you no longer have the option to turn VSA “on” or “off”. While it seems to be off by default at this point, it must be still trying to interpret road conditions occasionally causing the car to perform unexpectedly. Seems like a poor design. Once VSA it fails, it shoudn’t fight against the driver.
No, it is not the transmission. In short, the behavior of the car matches that of the description in the owner’s manual. In fact, turning the engine off allows VSA to reset itself. The car behaves fine, often allowing me to reach cruising speed before the VSA error message re-appears. Apparently, the VSA is tied into the ABS and acceleration. The jerky nature must be the ABS engaging erratically.
Stability control and traction control, which are two different (though related) computer-controlled systems that typically utilize the ABS (anti-lock brakes) system, have been phased in for most new cars over the past decade. It’s pretty clear you need to have a professional mechanic look at your CRV to determine exactly what is wrong. It wouldn’t necessarily have to be a Honda mechanic, though it would have to be a mechanic who could hook into a Honda’s computer and diagnostic system.
ESC/VSA watches individual wheel speeds and steering wheel position. It also monitors the chassis yaw rate (the rate at which the nose of the vehicle changes direction). If it makes a determination that the car is oversteering (rear-wheel skid) or understeering (front-wheel skid) or some combination of the two, it will apply braking effort to one or more of the wheels, and in some cases will also chop the throttle, in an effort to end the skid.
You didn’t mention any error message in your OP. Given that you are indeed receiving a VSA error message, it seems likely that one or more of these sensors has crapped out. Since you haven’t received an ABS error message, it seems likely that the wheel speed sensors are fine - which leaves the yaw rate sensor and the steering angle sensor.
I doubt a Ford guy will know the particulars of a Honda VSA system. However, there’s a chance that this will output a trouble code over the OBD2 diagnostic connector. The OBD2 connection is a legal requirement for all cars sold in the US since the mid-1990’s and is intended for diagnosing emissions-related malfunctions, but a lot of manufacturers use it for diagnosing other non-emissions issues (like ESC/ABS) as well. It’s the same connector and communication protocol, regardless of vehicle make/model/year, although the non-emissions trouble codes are often manufacturer-specific.
Some auto parts stores (in some parts of the country) will lend an OBD2 reader out for you to use in their parking lot (your Ford buddy may have one). In your case, hopefully Honda puts out VSA malfunction codes via the OBD2 connector, and you’ll be able to read what the VSA system thinks is wrong with itself. If you do this, you might just get a number code, which you’ll then have to Google for an interpretation.
In my Honda (if I’m to believe the manual) the default, at least in case of wrong tire-pressure readings (because of inflation or of sensor failure), is to VSA-on because it is a safety measure meant to limit you from driving “outside the envelope”. But as you say yourself, the issue is presenting itself in the situation when VSA is not supposed to be actively moderating you and that’s not how it’s supposed to do it. You are gonna have to get the codes.