Hi there,
I've got a problem that I can't lick. I am at my wits end and am trying to figure out a nice reward for the genius who solves my problem, so suggestions for the reward and the fix are needed.

Here is the problem:

I have a 1999 C5 with MN6, Z51, Magnesium wheels, HUD, and BROKEN ACTIVE HANDLING!

Here are the symptoms:

Sometimes, usually in a left hand turn, my car will start pulsing the brakes to (I think) the right front wheel. When this happens, my DIC displays, "Active Handling." I can feel the brake pedal pulsing when this happens. Sometimes this happens when going straight when I touch the brake pedal. Sometimes this happens when just cruising or in a right hand turn or bank. But usually, it happens during a left hand turn.
If I turn the AH off, all symptoms go away.

Here is what I have done so far:

Since this usually happens when turning left, I figured it might be the "Steering Position Sensor." I pulled the steering column and replaced this $150 part, but the problem did not go away.

So, I decided that it might be the "Yaw Rate Sensor." I replaced this, but the problem is still there.

Here is my logic behind my attempted repairs:
Steering sensor because left turns are usually where the problem occurs.
Yaw Sensor because its the only other part of the AH system that is not a shared component. See, the way I understand it is that AH uses some of its own parts and some of the ABS parts. When AH is turned off, the symptoms go away, but ABS still works. That makes me think that the wheel speed sensors are ok, but since I haven't fixed the problem, I could be wrong.

PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE
Help me fix this. I am going out of my mind and my dream car is turning into a nightmare.

The local Corvette shop could not figure this one out. I have posted here months ago and do searches to see if others have a fix. I have come up with nothing.

Thanks for any ideas, and remember, I will figure out some way to thank the Corvette God that identifies a fix.

Take care all,
Dale

PS. I have also forced the car into situations where AH need to catch the car and it does so perfectly. So AH can do its job, its just too eager to do it at times when it is not needed. Also, I will point out that this problem occurs at any speed, on smooth, sticky, dry surfaces. This is NOT a case of tires skipping over bumps and stuff.

 

Just to get a clear starting point do you have any codes showing up?

 

I forget the numbers, but the codes that show up are:

Short to left front turn signal (but it still works)
Short to right front turn signal (but it still works)
Error with left side, rear seat height sensor

And communications lost with right door control module
and left door module.

Thanks,
Dale

 

When you get a chance pull the codes again and notate which have a "H" suffix and which have a "HC" suffix. It's beginning to appear like you may have a general wiring problem. Have you checked to make sure your battery isn't leaking?

http://www.stengel.net/diccodes.htm

 

The battery is not leaking, but it is not the stock battery. Maybe the previous owner replaced it after some damage was done?

All the codes are followed by H. I will get the actual numbers soon, but I cleared them out last night, so they may not all be back yet.

Thanks for your time.
Dale

 

I would not rule out the wheel speed sensors. Check all the wires and make sure one has not been rubbing on the suspension.
When you make a left turn, the right wheel is turning faster than the right wheel, which might fool the system if something is not correct. What about the accelerometers?

Just some things to check

 

Well....after I first posted this question, I started looking through the maintenance manual and noticed the lateral accelerometer which is under the passenger's seat. I think I might replace this next, if I don't go broke. I did not realize there was such a beast until I saw it in the manual. How many other sensors are there associated with AH?

Dale

 

Perhaps this is a long shot but......

Owners of some Corvettes have experienced Service ABS, Service Active Handling and Service Traction Control messages. Wheel speed sensor codes may be set. This condition may be caused by replacing the OEM rubber brake hoses with aftermarket stainless steel brake hoses.

It is believed that the metal in the brake lines conducts static electricity, causing confusion in the wheel speed sensors.

The brake hoses must be returned to original rubber ones before the case can be investigated. This is a customer-pay expense.

and yes it sounds like BS to me.

 

Why not take it to your local Chevy dealer so they can place it on the diagnostics computer. You are throwing money at parts, but not diagnostics. The systems in the Vette and other complex vehicle's systems usually cannot be corrected using the method of "replacing parts till it works" method of auto repair, at least not economically.
If you are one that thinks that the techs at your local dealer don't know what their doing, you're doing yourself a great disservice. They have the equipment and know how to diagnose the systems on your Vette. You would be much better off having them diagnose the problem. Then, if you still wish to do the actual parts replacement yourself, take the diagnostics readout to purchase your replacement parts that they say it needs. This method probably would have saved you mucho $$$ in the long run already.

zo6vettepilot

 

Unfortunately, the diagnostics must be poor on the Active Handling issues. I was getting Service Active Handling, Service Traction Control, Service ABS alarms, intermittently. The dealer replaced the control module...nope, not it. The dealer checked and cleaned all the grounds...nope, not it. He then replaced the ABS pump. So far so good, but I'm not holding my breath. He spoke with the factory each time also. Oh, BTW, these were all warranty repairs.
Ed

 

This might sound stupid but, how are your rear brake pads? I once had a traction control problem on a C4 that no one could figure out and then I changed the brake pads and everything was ok.

 

You make a good point, but the problem with what you are suggesting is that it requires me write my Vette of as a "gonner" as far as I am concerned. I realize that the GM dealer has the tools, but so far I have not found a GM dealer in the Austin area that is not run by a collective of brain dead jack@rses. When I had my Z28 (2000), I had to get more repairs for what the techs broke during warranty work than for the original warranty issues.

Original Warranty Issues:
Bubbles between layers of windshield glass
Broken console cup holder
Oil leak
Sticking clutch pedal

Tech Caused issues:
Loose wiper arms due to windshield replacement
Scratched roof paint during windshield replacement
Dented and kinked drip rail around window during windshield replacement
Scratched radio surround while fixing console
Broke right front fender with lift during one of FOUR attempts to stop oil leak
Put LONG scratch in leather of steering wheel
Broke shift boot trim ring
Oil stain in drivers seat

In addition, the car is not under warranty, so I would have to pay ~100 hour for them to try and fix this.

I wish I was wrong, but so far, I cannot find a chevy dealer that has even a shadow of a clue when it comes to service.

If anyone can recommend a dealer that is good, please do so, but if you say Henna..... I would rather have Ronnie Milsap do open heart than have those guys even LOOK at my car.

PS Will they diagnose for a fee and let me do the work? That is IF I found a dealer I could trust.

 

Brake pads are pretty good. I probably have about 30% left.

Thanks everybody,
Dale

 

Thanks for the input, but I have stock lines.

Thanks everyone, please keep them coming.

If anyone can give basic instruction on how to check wiring, that would be wonderful.

Dale

 

Dale

I had a 98 that was an electrical disaster! I was lucky to get it to start and when it did start and run it would strand me on the road. Most of the time I was able to get it to LIMP home at 3-5 MPH!

I wanted to BURN the damn thing!!!!!!!!!!!!!!!!!!!!!

My problems were multiple issues that I solved ONE- BY- ONE on my own!

I found the following things wrong in this order.
-BAD TAC Module, Wet,

- BAD Corroded BCM circuit board due to clogged AC heater box drain and condensation dripping off the HVAC blower motor rubber vent hose.

- Bad battery! Battery cranked the car FINE but, the voltage output of the battery would dip down to or below 9 VDC for a fraction of a second during cranking. If you have random LDCM and RDCM error codes and or your FOB looses sync frequently this could be an issue.

- MAIN PROBLEM!!!! My under hood chassis grounds were SERIOUSLY corroded!! Check out this post:

http://forums.corvetteforum.com/show...al+information

After I PROPERLY cleaned the two chassis ground connectors ALL of my driveability issues are now RESOLVED!!!

I know that you said that the dealer cleaned the grounds but I have to ask which grounds (there are 13 + chassis grounds and many many more inside the dash and body and how good of a job did they do???

I like FREE repairs and checking the grounds is F R E E. Gige it a shot!

The C5 electrical system is very complex!! I strongly recommend fixing the known problems that you have with the:

Short to left front turn signal (but it still works)
Short to right front turn signal (but it still works)
Error with left side, rear seat height sensor

The light could be as simple as a dirty bulb contact.


Good luck!

Please let us know how you make out.

Bill C

 

Thanks Bill,
I will check out my grounds. I will be ecstatic if that is the issue.

I will keep updating this thread so you and others will know what the problem was if I ever track it down.

Dale