I just had new brakes put on and the rear end was leaking so that was fixed also (by a corvette specialty shop, not a dealer) . When I drove away after a few minutes, I got an "active handling warming up" message. Then a "service active handling" and a "service vehicle soon" message. If I reset, they go away and the active handling icon is lit. The shop said its the steering wheel angle sensor, I think they tried to re-program it. I never had any active handling messages ever but after all the work I had all of a sudden these messages start. Any thoughts? Thanks in advance.

 

What codes are thrown? 1287?

 

Not sure, its back at the shop.

 

Sounds like someone forgot to plug in a wheel speed sensor when they put the rear end back together. Hard to believe they were messing around in the rear near parts related to the active handling system and for no reason the SWPS just happened to fail the same time. Occam's razor: the simplest answer is usually the right one.
Btw you can't reprogram a SWPS or really any sensor.

 

Active Handling Warming Up isn't necessarily bad message. Here is a copy of a section of an SAE paper where GM engineers describe how active handling works and why Active Handling Warming Up messages appear. There are two conditions on the C5 when the Active Handling Warming Up message can be seen.From SAE Paper

COLD AMBIENT - The thermal gradient of the engine compartment was measured at various ambients to establish the time it took for the hydraulic modulator to become warm and capable of full pressure response. When the vehicle is first started in cold weather and driven forward (>10 kph), the passenger zone module (PZM) monitors the engine intake air and coolant temperatures. The PZM contains software logic to determine if the hydraulics are cold (<=-10C), and if cold, the cluster is instructed to display the message " Active Handling Warming-up". The system is functional but the first cycle performance can be affected until the next message "Warm-up complete" is displayed. Traction control and ABS actuations prior to Active Handling actuations will improve the cold hydraulic performance.

SYSTEM INITIALIZATION / SENSOR CENTERING

The yaw rate sensor and steering wheel angle sensor must be centered after each ignition off-on cycle. AH will not function until centering has occurred. CENTERING - The steering wheel angle sensor is centered every ignition off-on cycle This creates a more complex control algorithm but offers significant logistical advantages at the vehicle assembly plant and vehicle service centers. The Corvette assembly plant does not have to communicate with AH to assure centering. Service centers making repairs to the suspension, steering or replacing the steering sensor, do not have to communicate to the AH system. The AH system requires that the vehicle be driven while the system completes the centering routine.

The yaw rate sensor centers quickly if the vehicle is stationary or driven in a straight line. The yaw rate centering time increases with steering inputs >20 degrees or when the vehicle ignition is cycled to crank while the vehicle is moving.

The steering wheel angle sensor has a digital and analog signal output to the electronic control module (ECU). The AH centering algorithm uses the last "centered" analog value from the previous ignition cycle to quickly center the digital steering wheel angle value. The first ignition cycle at the car plant or after the ECU has been disconnected for several hours during service will require the longest time to center. The digital steering wheel angle value is put through a sanity check to make sure that the centering value is accurate. A sanity check requires driving the vehicle in a straight line after ignition off-on. The time for the sanity check increases with steering inputs .+-20 degrees.

INITIALIZATION - Under normal driving conditions the yaw rate and steering angle sensors will be centered and the AH system initializes within seconds after driving the vehicle forward. However, if for some reason, one or more sensors have not centered and the driver has exceeded 20 kph for a period of time, the PZM will command the DIC message displayed "Active Handling Warming Up", and a icon will be illuminated. This message can be acknowledged and erased from the display. When the centering conditions have been completed the next message "Warmup Complete" will be momentarily displayed, and the icon turned off. The system is functional. lf the system never centers the "Service Active Handling" will be displayed.

The last condition sounds similar to what you are experiencing. When they did the work on the rear of the car it sounds like they may not have gotten rear toe set correctly when they finished the repair. The Active Handling Warming Up message you are getting indicates the steering isn't centered, the following message Service Active Handling indicates the system wasn't able to center itself for the straight ahead direction over a certain period of time and the system set a centering code.

If your steering wheel has to be offset to the left or the right over a certain amount so you can drive straight down the road the front steer ahead adjustment may be off or the rear thrust angle may be off. Getting those two adjustments within specification may rid you of the messages. There isn't much they could do to the steering sensor if they only removed the rear axle or the diff to fix a leak. However, whatever they did may require them to adjust rear toe when the car was put back together and they may not have done that correctly.

A broken or disconnected wheel speed sensor wire wouldn't cause that combination of errors. When a wheel speed sensor is not sending it's signal to the EBCM you will get Service ABS, Service TC and Service AH messages since a missing wheel speed signal shuts down all functions of the EBCM not just one so there is no need to look for a wheel speed sensor wiring issue.

The code generated by the EBCM will probably say something about the steering sensor and the diagnostic for that code starts by telling the mechanic to check toe settings.

Bill

 

Thanks everyone, still waiting on the shop. They have tried 4 or 5 steering wheel angle sensor's and still get the same message. They tell me they are sure its a bad sensor. Supposed to hear more again today.

 

If they have tried 4 or 5 sensors with no luck.....it's NOT the sensor !!!

 

Absolutely most definitely without a doubt THIS. TAKE IT TO A DIFFERENT SHOP

 

What section of the country are you located ??...I may be able to direct you to some good diagnostic guys !!

 

Chicago suburbs.

 

Chicago ??...you're in luck !!...John Thornton is the country's pre eminent auto diagnostic guru and the top

instructor hands down !!. He does mobile diagnostics to repair shops in the Chicago area but I don't know if he will come to you directly. Info below !!

 

My car had this exact issue when i bought it a a few years ago. there really aren't that many things that it could be to cause those exact symptoms. In my case is was an issue with the steering wheel position sensor, well not really the sensor, more who ever had last worked on the car. The steering wheel was simply spun 360 degrees so the sensor was reading that i was turning hard when in fact i was going straight. Clearly thats not ur problem. However, theres really only two other possibilities to the best of my knowledge. One is that the active handling module is bad, this is pretty rare. The other is that its not getting the correct signal from one of the four wheel speed sensors. My guess is that your "specialty shop" damaged a sensor, damaged the wiring harness near the sensor, or simply pulled on the sensor wires and broke connection at the sensor. All of this could easily happen when working on the breaks if your not carful. Its really the only thing that makes sense, it cant be a coincidence that it "magically" happened after they worked on the car.

 

I've had this light on since I installed headers in my99 years ago. But I'm OLD and never had this system before. I know how to drive. LOL
But with this thread, maybe someone here can instruct me on how to 'center' the SWPS???
Or at least how to test it.
I'm pretty sure I turned the steering wheel while doing the headers. Hey, nobody ever said I'm smart.

 

This is highly unlikely as the sensor is discontinued and no longer available. I know this as I am trying to decide what to do about my bad sensor on my '99. They are only available used for around $400 and it's an involved process to replace the sensors, dealer quoted me $500.

 

If you can contort yourself to get the leads of the sensor with a multimeter. With the wheels pointed forward you should see 2.5 volts DC. If you don't, then try turning the wheel 360 deg one way or the other. If you find where the correct center is, disconnect the steering shaft from the rack and correct the wheel rotation.

 

I got it back last weekend and its fixed. They said it was the the steering wheel angle sensor and they finally found a used one that was good.

Thanks everyone!