I recently had a clutch replaced (upgraded), and now 3 nights in a row driving home on the freeway doing ~70 mph the "active handeling" indicator in the DIC has turned on. I can feel the car wiggle a little and a little power drop, then it turns off and it is fine. it did this 4 times in 2 miles.

Oddly on the way to work nothing happens.

why is it doing this? something possibly loose?

I also have zero codes....

 

I don't have an answer but mine will occassionally come on as well. Just out of the blue after driving for a few hours it will say active handling warming up. Who knows. I never notice any difference in the way the car feels.

 

What's really going to cook your goose is when it locks one of the front brakes as you're doing 70-75mph - trust me when I say this is the single most terrifying incident I've been thru with a car.

I'm convinced this system should be disabled permanently - when I figure out how to do it, it will be. There are those that love AH, but for me, I can do without it. The last thing I need is a car making unwanted decisions for me.

 

Hmmmm.. I'd take it to whoever did the clutch (yourself?) and re-check everything. It seems like the system is detecting rear-wheel slip; ie; the engine revs/vehicle speed aren't matching what the computer thinks wheel rotations should be. Check your clutch fluid reservoir.. black or nice 'n clear? Any slippage? How recent was the upgrade? Did you drive it hard before the clutch was broken in?

mymaur: you should have the whole brake system checked. I believe the "warming up" message comes on when the ABS/AHS is checking it's fluid reserves and equalizes it.

everyone just check yer danged fluids

 

I had the clutch done by andy at A&S corvette.

I called him and he said it should have nothing to do with what he did to the car.

I have not broken the clutch in yet, I am only cruising it. I have about 250 miles on it, and it was done 3 weeks ago.

It never did this in my 3 years prior owning it.

the clutch was going to be a textralia twin disk, but I ended up with a carbonetic triple disk which is not available yet. It appears I have the 1st one and it is suppose to be good for 1000 hp even though I am stock. Andy was out of the textralia and shoved this in instead.

The web site says to break it in for 800-1000 miles and not to do this and that.

I will check the fluid, and be very pissed off is it is already dirty.

 

clutch fluid is perfect. looks all new.

 

Maybe you're not telling us the whole truth about what your right foot is doing.......

LOL! I'm kidding man. IDK what to tell you. Was there any water on the road?

 

That's the first thing they teach auto tech's to say. My guess is he/someone who worked on the car messed up the wires to one of the wheel speed sensors.

 

so I have been doing it 100% all week on the way home only.

I drive the same freeway both ways. driving the same does not trigger it in the morning.

last night as soon as I got on the freeway it kicked on ~60 mph.
I tried 5th gear it does it still.
I went into competive mode and it stopped... why? I thought comp mode was just active handeling?

Anyhow it does not do it in the late morning which has been around mid to high 60 degrees out. at night it is low 50's and it does do it.
I guess for lack of other reasons I am looking at something temp could effect?

I further checked tire pressure and they are good.

 

Bill,

Pull each wheel & examine (disconnect/clean/reconnect) the speed sensor wires.

 

CleteZ16 - Active Handling (AH) has nothing to do with rear wheel slip ... that is Traction Control (TC). TC uses the four wheel speed sensors and compares rear wheel speeds to front wheel speeds. Once they differ by a pre-programmed amount the TC function is activated. Clutch slip would not cause a TC event (or an AH event) ... the EBCM does not even know what the engine RPM data is.

The "AH Warming Up" message is generated when the EBCM needs to calibrate the Steering Wheel Position Sensor (SWPS) ... and conditions to perform the calibration have not yet been met.

bill mcdonald .... Using the DIC check to see if there are any codes set in the EBCM ... go here if you don't know how to display DTC data on the DIC ....

https://www.corvetteforum.com/techti...D=26&TopicID=1

The majority of the time, unexpected AH intervention is caused by an intermittent failure of the SWPS. Do you get "AH warming up" messages ??? Especially after you've been driving a while ??? Also check the grounds for the EBCM, they are located at G103 and G108. See Bill Curlee's sticky at the top of the C5 TECH forum on electrical issues if you need help locating these ground points.

 

No codes.

I have not seen the AH warming up display come up in years.

 

I'd recommend you check the grounding of the EBCM, as I mentioned above.

If the grounds are clean, and the problem continues, and there are no DTC being posted, then "throwing parts" at the problem is about your only choice (or live wit the problem until a DTC sets giving youa clearer indication of the problem).

There are three sensors that the AH system uses, the SWPS, a yaw sensor, and a lateral acceleration sensor. Most of the time it is the SWPS that has problems, so if you want to ttry fixing it, try replacing that first.

 

Man.. BlackZ06 reallly knows what he is talking about.... Did you ever run into the problem yourself???

 

doing an O2 sensor change (I have to smog the car), I disconnected the battery durring this time, which for some reason must of reset the computer better then the other 3 times I left it disconnected since this issuse came along.

Oddly enough when I went for a 65 mile drive, I finally got a code, and an error message in the DIC. the system must of went off a dozen times before it threw out a code.
1288

I am doing a search right now for what that is. I read something earlier this morning about the steering position sensor. Great!!!

I also completly removed the ground, and cleaned everything till it was shiney and dirt free

 

DTC C1287 or C1288
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
The ignition is ON.

Conditions for Setting the DTC
C1287
One of the following conditions exists:

The steering wheel position sensor is synchronized and the steer rate (speed that the steering wheel appears to be turning) is greater than 1100 degrees/second.
The steer rate is less than 80 degrees/second and the difference in the phase angle between Phase A and Phase B is greater than 20 degrees.
The 2 steering sensor signals (Phase A and Phase B) do not agree for 1 second. Under this condition, this DTC will set along with DTC C1281.

C1288
One of the following conditions exists:

Both Phase A and Phase B are greater than 4.9 volts for 1.6 seconds.
Both Phase A and Phase B are less than 0.2 volts for 1.6 seconds.
The difference in the changes in Phase A and Phase B is greater than 35.2 degrees for 9.76 milliseconds.

Action Taken When the DTC Sets
The EBCM disables the VSES for the duration of the ignition cycle.
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.

The ABS remains functional.
Conditions for Clearing the DTC
The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The scan tool may display 2 additional characters after the DTC. Take note of the 2 character code and any other DTCs that are set. The 2 character code is an engineering aid used in order to determine the specific criteria which caused the DTC to set.

During diagnosis, park the vehicle on a level surface.

Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface.
Find out from the driver under what conditions the DTC was set (when the DIC displayed the Service Active Handling message). This information will help to duplicate the failure.
The Snapshot function on the scan tool can help find an intermittent DTC.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

Step 2. Perform the Steering Position Sensor Test in order to verify if the steering wheel position sensor (SWPS) is operating properly.

Step 3. Tests for the proper operation of the steering wheel position signal A circuit in the low voltage range.

Step 4. Tests for the proper operation of the steering wheel position signal B circuit in the low voltage range.

Step 5. Tests for the proper operation of the steering wheel position signal A circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Step 6. Tests for the proper operation of the steering wheel position signal B circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Step 7. Tests for a short to voltage in the 5 volt reference circuit.

Step 8. Tests for a high resistance or an open in the low reference circuit.

Step
Action
Values
Yes
No

Schematic Reference: ABS Schematics

Step 1
Did you perform the ABS Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - ABS

Step 2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, perform the Steering Position Sensor Test.
Did the SWPS pass the test?
--
Go to Diagnostic Aids
Go to Step 3

Step 3
Turn OFF the ignition.
Disconnect the steering wheel position sensor (SWPS) connector.
Turn ON the ignition, with the engine OFF.
With the scan tool, observe the Dual Analog SWPS Input A parameter in the VSES data list.
Does the scan tool indicate the Dual Analog SWPS Input A parameter is less than the specified value?
0.2 V
Go to Step 4
Go to Step 13

Step 4
With the scan tool, observe the Dual Analog SWPS Input B parameter.

Does the scan tool indicate the Dual Analog SWPS Input B parameter is less than the specified value?
0.2 V
Go to Step 5
Go to Step 14

Step 5
Turn OFF the ignition.
Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the steering wheel position sensor (SWPS) and the signal A circuit of the steering wheel position sensor (SWPS).
Turn ON the ignition, with the engine OFF.
With the scan tool, observe the Dual Analog SWPS Input A parameter.
Does the scan tool indicate that the Dual Analog SWPS Input A parameter is greater than the specified value?
4.9 V
Go to Step 6
Go to Step 10

Step 6
Turn OFF the ignition.
Disconnect the fused jumper wire.
Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the steering wheel position sensor (SWPS) and the signal B circuit of the steering wheel position sensor (SWPS).
Turn ON the ignition, with the engine OFF.
With the scan tool, observe the Dual Analog SWPS Input B parameter.
Does the scan tool indicate that the Dual Analog SWPS Input B parameter is greater than the specified value?
4.9 V
Go to Step 7
Go to Step 10

Step 7
Disconnect the fused jumper wire.
Measure the voltage between the 5 volt reference circuit of the steering wheel position sensor (SWPS) and the low reference circuit of the steering wheel position sensor (SWPS).
Does the voltage measure less the specified value?
5 V
Go to Step 8
Go to Step 9

Step 8
Turn OFF the ignition.
Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
Measure the resistance from the low reference circuit of the steering wheel position sensor (SWPS) to a good ground.
Does the resistance measure less than the specified value?
5 ohms
Go to Step 16
Go to Step 15

Step 9
Test the 5 volt reference circuit of the steering wheel position sensor (SWPS) for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 17

Step 10
Test the 5 volt reference circuit of the steering wheel position sensor (SWPS) for the following conditions:

An open
A short to ground
A high resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 11

Step 11
Test the signal A circuit of the steering wheel position sensor (SWPS) for the following conditions:

An open
A short to ground
A high resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 12

Step 12
Test the signal B circuit of the steering wheel position sensor (SWPS) for the following conditions:

An open
A short to ground
A high resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 17

Step 13
Test the signal A circuit of the steering wheel position sensor (SWPS) for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 17

Step 14
Test the signal B circuit of the steering wheel position sensor (SWPS) for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 17

Step 15
Disconnect the EBCM harness connector.
Install the J 39700 universal pinout box using the J 39700-300 cable adapter to the EBCM harness connector only.
Test the low reference circuit of the steering wheel position sensor (SWPS) for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 20
Go to Step 17

Step 16
Inspect for poor connections at the harness connector of the steering wheel position sensor (SWPS). Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 18

Step 17
Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 19

Step 18
Replace the steering wheel position sensor (SWPS). Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle and Steering Shaft, Lower Bearing, and Jacket - Assemble - Off Vehicle in Steering Wheel and Column - Tilt.

Did you complete the repair?
--
Go to Step 20
--

Step 19
Replace the EBCM. Refer to Electronic Brake Control Module (EBCM) Replacement .

Did you complete the repair?
--
Go to Step 20
--

Step 20
Clear the DTCs using the scan tool.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
--
Go to Step 2
System OK

Hope this helps it is from the 01 Service Manual.

Bill

 

Sounds like a cold tire worn out tire problem to me.

Also, areas have been dropping in temp below what your seeing in the valley.

Right after sunset it is getting downright nippy.

 

Ive never had AH warming up displayed on the DIC.

 

Guys .... AH WARMING UP is not a heat related issue. When you first start the car, or any time the EBCM thinks it has lost "calibration" of the Steering Wheel Postion Sensor (SWPS), then the EBCM re-calibrates the SWPS. If it cannot accomplish this calibration within a set time, it issues the WARMING UP message to indicate that the AH system is unavailable until the calibration is complete.

Calibration requires the vehicle to be travelling straight down the road. The EBCM knows the car is going straight because it has speed readings from the wheel speed sensors, and the yaw and lateral accelerometer are reporting ZERO. The vehicle must be at a speed of at least 6 MPH on a level surface for at least 10 seconds for the SWPS calibration to occur.

AH WARMING UP messages that occur after you've been driving the car a while (the EBCM has successfully calibrated the SWPS already) are an indicator that the SWPS is getting flakey.

 

I was refering to cold tires and cold streets.

When it is cold out (as it has been lately) my Vette loses grip fairly easy.