New subscriber with very little knowledge of tech stuff, so please be gentle. I have been having a problem with my active handling for over a year and had no idea what it was, or what to do about it. Symptoms: jerking, felt as though the brakes were being applied. First time I took it to my dealer they couldn't find anything wrong. I no more than left the dealership, and it happened again I called my service adviser who told me that the tech couldn't find a problem, and there were no codes. He also mentioned that the codes don't stay for long. This past week I returned and later the advisor called me to say that my battery had a bad cell, and needed to be replaced before the tech could run the diagnostic. After waiting for four days, I finally told the advisor that I needed the car back, and to button it up, and would return when I had more time. He then told me that the battery must have been the problem because after running the diagnostic, he couldn't find any problem. Just this morning the problem returned. Short of finding a new service person, I'm hoping someone can help.

 

faulty wheel speed sensor (or loose plug,broken wire for the sensor most likely)...you can pull the plugs at each wheel and make sure they are clean and tight just to be sure but if I had to guess you have a faulty speed sensor...I would say maybe SWPS but that leaves a code although a faulty speed sensor should too


someone with a Tech 2 could ride along and diagnose easily....surprised you are not seeing a TCS code flash on the DIC when it happens

 

Do a search on the forum on how to pull codes from the DIC and post what you find. I had this problem recently and the fix depended on the codes.

 

The active handling system is reset with each engine start. That is why the codes disappear. Each time the engine is started the ABS recalibrates the signals coming from the steering sensor so the EBCM knows which steering wheel position is straight ahead. Active handling works by applying a single brake or a combination of brakes to control understeer or oversteer. Inside rear brake is applied to make the car turn more if the car isn't turning fast enough to follow the driver's steering input and if the car is turning faster than the driver's steering input is directing it then the outside front brake is applied to keep the back end from swinging around.

Any wheel sensor failure kills the system and ABS, TC and AH are all turned off and will not activate. You will know this when you get the Service Message for all three systems on the DIC. From your description of what is happening it looks like the wheel speed sensors aren't the problem as you don't say anything about any messages or lights on the instrument panel (not CEL, the other lights).

Since you don't mention any messages or lights I suspect you could have either a wheel alignment issue or a steering sensor that is starting to fail. If the steering wheel isn't centered the EBCM may think your car isn't responding properly to a turn whereas a faulty steering sensor can tell the EBCM you are making a turn when you aren't. If they are too far out of range you will get codes but there are interface tolerance issues with every system made by humans and your car may be in the middle of one of those. A bad battery can make the system more sensitive to signal errors as the signals are dependent on certain supply and reference voltage levels. Poor electrical connections at all wiring terminals/connectors due to corrosion/dirt can lower the voltage as well.

The next time you get the pulling/jerking pull over some place safe, note all of the instrument panel lights and DIC messages and then before turning off the engine use the DIC control buttons to turn the On Board diagnostic system on and read all of the codes.

Hopefully, you get a chance to catch a diagnostic code.

Bill