Traction Control issue in 2003 auto D2 non-ACE with air springs.

The TC occasionally operates when the NSF wheel encounters a pothole or road hollow and engages the NSF brake with sufficient force to pull the steering to the left. Previously, the TC would operate randomly when 'making progress' even on steep ascents and operate the NSF brake as above. The TC can be reset by a swift tap of the brake pedal. HDC functions as expected as does ABS. I have not had the opportunity to test the TC in a muddy field or similar since starting to investigate this problem but it has previously worked as expected.

I have replaced: ABS unit and NSF ABS sensor (with NSF hub as it was deemed prudent to do so at the same time as the sensor because the hub was looking pretty rough).

There are no ABS fault codes and the ABS sensors return identical dynamic readings (although this has not been checked over a TC-activating pothole).

"Avoid potholes" is not the answer because I am using the term to describe any fierce road depression

Judging from the wiring diagram, the ABS sensors connect to SLABS/ECU and that drives the ABS modulator. Is that correct?

Suggestions as to what to try next, please.

There is a missbalance between the sensor's readings which can have various causes even different brand sensors can cause that or if the air gaps are not perfectly set, a play in the reluctor ring, some cheap huibs have wrong number of teeth on the ring(55 instead of 60), etc... tester is needed to read live inputs to see which wheel is causing that cos it's not necessarily on the wheel which is braking cos it can be on the other one as if it's input is lower at the same speed the TC will put the brake on the one which has the higher input considering it slipping

sierrafery said:

There is a missbalance between the sensor's readings which can have various causes even different brand sensors can cause that or if the air gaps are not perfectly set, a play in the reluctor ring, some cheap huibs have wrong number of teeth on the ring(55 instead of 60), etc... tester is needed to read live inputs to see which wheel is causing that cos it's not necessarily on the wheel which is braking cos it can be on the other one as if it's input is lower at the same speed the TC will put the brake on the one which has the higher input considering it slipping

Click to expand...

Thank you.

[1] the dynamic readings, i.e. whilst driving, from the ABS sensors are identical. However, I have not observed the reading in a trigger situation.
[2] the replacement hub was genuine and was supplied with the ABS sensor installed.
[3] the symptoms are marginally better since changing the NSF sensor and hub.
[4] the erroneous operation only occurs after encountering a sharp depression with the NSF wheel.
[5] Hmm, hadn't considered that the OSF wheel might be measured as travelling faster than the NSF :-(

Reference [3] prior to changing the hub and sensor, the TC had operated when pressing-on with vigour in a few other situations: once when I encountered a deep puddle at ~ 50mph on a level road and a couple of times, again on wet roads, when climbing steep roads at speed with considerable acceleration to maintain momentum. Again a single brake operated and the steering pulled left. I have not had an opportunity to attemtp to reproduce the speed/acceleration/water test yet.

One other thing; once the TC has begun operating in this condition it does not disengage without intervention from me.

I'm not saying that you are wrong, just adding my thoughts to your comments.

Wouldn't a miss-match between the number of teeth on the reluctor ring of one hub cause a continual operation of the TC?

What do you think?

TIA

Richard