Pulled the code and found out what it meant, but can't figure out what a VSES sensor is, or where it's at.

Anyone?????

 

Circuit Description

The vehicle stability enhancement system (VSES) is activated by the electronic brake control mdoule (EBCM) calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.

The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the drivers steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.

The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.

Conditions for Running the DTC C1281

The steer angle has been centered.
The VSES is active.
The direction (understeer or oversteer) of the delta velocity error has not changed.
The centered lateral acceleration value is less than 0.5 g.
The yaw rate error is less than 6 degrees/second.
The side slip error is greater than 1.8 meters/second*second.

Conditions for Setting the DTC C1281

One of the following conditions exists:

The VSES is engaged for 10 seconds with the delta velocity error always in either understeer or oversteer. Under this condition, this DTC will set by itself.

The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1282.

The yaw rate error is greater than 10 degrees/second with the vehicle speed less than 60 km/h (37 mph) and the acceleration pedal is pressed more than 25 percent of the pedal travel range for 1 second during the VSES activation. Under this condition, this DTC will set along with DTC C1282.

With the yaw rate less than 8 degrees/second, the side slip error is greater than 4.9 meters/second*second for 5 seconds. Under this condition, this DTC will set along with DTC C1284.

With the vehicle speed greater than 10 km/h (6.2 mph) and less than 100 km/h (62 mph) and the centered yaw rate has a value that is positive and is greater than 10 degrees/second, the oversteer term is negative for 2 seconds. The oversteer term is the yaw rate value times the lateral acceleration value. Under this condition, this DTC will set along with DTC C1284.

With the steer rate less than 80 degrees/second, the difference between the 2 steering sensor signals (Phase A and Phase B) is greater than 20 degrees for 1 second. Under this condition, this DTC will set along with DTC C1287.

 

Thanks for the reply Patches.

BTW, did you pull all that off the top of your head??
That's a whole lot of info.

Judging from what I read I'm guessing those little lane marker bumps the state puts on the highways may have triggered the code, or maybe it's time to take a good look at the bushings on my suspension. They are 6 years old by now, and have been subjected to some 'aggressive driving', as pointed out in your reply.

Thanks again for the info.