VW T6: Traction Control Light: Turning left/right

[Timmy_T6]

Hi all,

Last week my traction control would keep coming on when turning left/right at relatively low speed. No fault codes.

Van had been sat in my garage last 2 weeks while I swapped headlights - can't see how this would effect anything.

I checked for obvious signs of cable issue (visually) in case I knocked a cable and cleaned abs sensors. Found nothing except front nearside front abs sensor being covered in grease - no codes & no change.

Took it to local garage who struggled and suggested replacing x4 abs sensors, after logging the wheel speed none showed an obvious fault but nearside front was about 10mph different a couple of times. Should mention, the rear wheels when the traction control light comes on, are about 5mph lower than the fronts (turning at about 30mph round big roundabout).

Then they recommended replacing front nearside hub, no change. No codes etc.

I've searched and can't find any similar posts where anyone has had this issue, its booked in for tomorrow but in all honesty I don't think they have anymore ideas than me.

My thoughts are its the ABS unit or perhaps to try replacing the other hubs??
Any ideas where to look next welcome.

Thanks!

Engine (2D2D2-CXHA)
Chassis Type: 7H-VN75 (7E0)

 

[mmi]

Please check the fuses
SB16, SB17 (fusebox by left headlight)
SC32, SC51 (centre fusebox in cabin)

Please post the following

1) Full VCDS Auto-Scan​

​

​

Blockmap files as follows

Ignition ON/engine OFF (twiddle steering after turning ignition on)

2) 03-ABS blockmap​

3) 04-Steering angle​

4) 17-Instruments blockmap​

Engine idling - after starting the engine turn steering wheel 90 degrees to the right

5) 03-ABS blockmap​

6) 04-Steering angle​

7) 17-Instruments blockmap​

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How-to create a blockmap file:

[VCDS]​

[Applications]​

[Controller Channel Map]​

- Single Controller Address = 03 (and 04, 17)​

- Login or security access code: Leave blank​

- Function: Measuring values​

- Output: CSV file​

[Go]​

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The result (TXT and CSV) files are saved into directory C:\Ross-Tech\VCDS\Logs
Please attach the files here.

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Meanwhile, check this

Thread 'ABS/Traction control lights still on'

21 Nov 2024

Hi guys, looking for help. I have a ABS/traction control light on with no fault codes. I have a topdon scanner it didn’t show errors and all 4 wheels displayed accurate speed readings. I’ve been to a local VW specialist that has been recommended on various forums. Due to no faults they tried to reprogram the ABS module but it failed. They advised me to get a second hand ABS module and have it fitted. I got an ABS module off Ebay from another VW T6. It was programmed successfully but when the mechanic bled the brake system using a professional scanner the bleeding process failed to be fully...

• dinz_dinz
• abs traction control
• Replies: 25
• Forum: Suspension, Steering, Brakes

 

[Timmy_T6]

Hi @mmi blockmap files

 

[Timmy_T6]

Hi @mmi autoscan attached.

Fuses were ok.

Hoping you can help as local garage said they can't help further and recommended I take it to vw unless we can identify whats causing the issue. They were doubtful about the abs module as can't understand why the light (taction control) only comes on when turning??

 

[mmi]

Thanks for the files.

traction control would keep coming on when turning left/right at relatively low speed.

So the light comes on only when moving?
Asking as there were no indication/signs of the light being on in the files.

So nothing too suspicious, well, except the below (nonzero) is something I've not seen. Has the basic setting been applied to the ABS recently? Would have expected to see plain zero.

nearside front was about 10mph different a couple of times

Should mention, the rear wheels when the traction control light comes on, are about 5mph lower than the fronts (turning at about 30mph round big roundabout).

I would expect the above would indeed turn on the light.

Could you make a log of the following please - preferably hit marker when light turns on.

Ignition ON

VCDS > Select > 03-ABS > Adv. Meas. Values

Tick the data items

IDE02986-IDE04431 Indicator lamps-ASR and ESP indicator lamp​

IDE04425-IDE00920 Left front ABS wheel speed sensor-Front left wheel speed​

IDE04426-IDE00921 Right front ABS wheel speed sensor-Wheel speed: right front​

IDE04427-IDE00922 Left rear ABS wheel speed sensor-Left rear wheel speed​

IDE04428-IDE00923 Right rear ABS wheel speed sensor-Right rear wheel speed​

IDE04443-IDE02241 Slip control system sensor-Lateral acceleration sensor 1​

IDE04443-IDE02538 Slip control system sensor-Longitude Acceleration Sensor​

IDE04443-IDE04429 Slip control system sensor-Lateral acceleration sensor 1: offset​

IDE04443-IDE04430 Slip control system sensor-Longitudinal acceleration sensor: offset​

IDE04443-IDE04449 Slip control system sensor-Rotation rate sensor 1: Z-axis​

IDE04443-IDE04460 Slip control system sensor-Steering angle sensor: offset straight line running​

IDE04443-MAS00815 Slip control system sensor-Steering angle sensor​

Tick

verify the data is alive

Log > filename > Start (the logging - IMPORTANT!!!)

Start the engine, and drive around so the traction control light turns on and include also some straight line driving.

Stop (the logging), etc.

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The result files are saved into directory C:\Ross-Tech\VCDS\Logs

 

[Timmy_T6]

Hi @mmi thank you for taking the time to look through this!

Traction control lamp only comes on when turning left/right (flashes) and at speeds roughly above 15-20mph~, you can also feel brakes being applied.

To give context, I have rarely ever had a car apply this level of traction control, and I was going a lot faster than 20mph, I can only assume somewhere in the van it "thinks" we are travelling much faster than we are or it "thinks" we are in a spin/skid like the back end of the van is sliding. Something like that anyway, when we clearly are not.

Has the basic setting been applied to the ABS recently?
Yes, one attemp to remedy the issue was a wheel alignment. Straight after the alignment the traction control light and one other light came on (sorry can't remember) but I read this can happen after an alignment from a post on this forum, it said to perform basic setting and these cleared. Logged the scan first if you need it. But, this was after the issue started and was an attempt to solve it, which it did not.

Attached file has two logged runs. Sorry but the 1st started after we were under way already.

2nd run followed your post instrunctions to the letter.

My glamorous assistant wasn't sure how the marker button worked, neither did I, so best to count that with a pinch of salt, I guess looking at the file she was clicking when lamp was on and then when off, rather that pressing contantly - we can have another go if needed.

One thing surprise me is the "Indicator lamps-ASR and ESP indicator lamp" on/off: as the lamp is flashing much longer that it appears by the number of "on" in the file, not sure about that.

I'm not seeing any correlation between wheel speed and the lamp - hoping this means more to you.

Many thanks!!

 

[mmi]

Thank you for the logs - quite fascinating...

My glamorous assistant wasn't sure how the marker button worked, neither did I, so best to count that with a pinch of salt, I guess looking at the file she was clicking when lamp was on and then when off, rather that pressing contantly - we can have another go if needed.

Yes, perfect. Just click whenever something happens/stops. They just help to pinpoint the moments of interest.

Interestingly there are gaps in the data flow which coincide with marker button clicks. During the 2nd run there was even a 10 second gap in the data flow.

Green blocks are markers made by your assistant. Red blocks ASR/ESP lamp data.

Worth noting that VCDS records data only when available on the CANbus - thus manual timestamps have been delayed in the gaps (not recorded alone but "paired" with actual data).





So either a glitch in VCDS, but I would think it's too much coincidence with manual markers.

Perhaps the ABS controller itself is the culprit? Still remains the mystery why it's steering related?

If interested would propose to make a recording of monitored ABS power supplies

IDE00780 Mode​

IDE02986-IDE04431 Indicator lamps-ASR and ESP indicator lamp​

IDE03527-IDE02070 CAN signals-Wake-up cause​

IDE03680-IDE00018 Supply voltages-Voltage terminal 15​

IDE03680-IDE01232 Supply voltages-Supply voltage for external components​

IDE03680-IDE04444 Supply voltages-Terminal 30 voltage for pump​

IDE03680-IDE04445 Supply voltages-Terminal 30 voltage for valves​

IDE03680-IDE04500 Supply voltages-Terminal 30 voltage for logic​

IDE04425-IDE00920 Left front ABS wheel speed sensor-Front left wheel speed​

IDE04426-IDE00921 Right front ABS wheel speed sensor-Wheel speed: right front​

 

[Timmy_T6]

@mmi thanks for the data analysis - thats quite impressive!

Its all very strange and has left me with more questions:

1. If the power supply is dropping why do we not have a fault code?
2. If the voltages are dropping, how do we determine if the fault is wiring or the ABS controller?

I'm guessing you are one step ahead and the new log will go some way to help answer these

We shall go on another roundabout log run tomorrow and post the updated log...

Thanks again.

 

[Timmy_T6]

Hi @mmi,

We completed a run where we were careful to mark when the light was flashing, my assistant did a very good job I think!
I have discussed the situation on other forums and after reading your first post where you shared another similar story I have a refurbished pump/controller on route. Its got a 28day return so thought if it was anything else I can send back.

I'm not seeing a voltage drop when the lamp is activated.

From this data do you think replacing the module and/or pump is the right way to go in your opinion?

Many thanks for the support!

 

[mmi]

I'm not seeing a voltage drop when the lamp is activated.

Agree - no glitches in voltage supplies.

From this data do you think replacing the module and/or pump is the right way to go in your opinion?

Nothing on sensor data (wheel speed) show anything wrong. Well, having another look into the accelerator sensors data they show (in my opinion) quite high accelerations (both lateral and longitudinal, up to 0.4g both negative and positive) at the moments of markers. The wrong acceleration data certainly would trigger traction control - did you drive aggressively? Well, the sensors are internal of the controller anyways.

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Anyways, today's data has no gaps in the data. However, it seems you forgot to tick "Group UDS requests" and thus data sampling rate was today siginificantly slower (0.8 seconds vs. 0.2 seconds on yesterday). Interestingly tha gaps yesterday coincided with traction control light.

Below a sample of today's data (same 25 second snippet but less data points).
The bottom curve is speed difference between front wheels - normal as obviously were turning left/right.

 

[Timmy_T6]

I did indeed give it a little more poke around the bends, my thinking was that if there was/is a loose connection etc then this would give more data to try and pinpoint where it was coming from.

Disappointed I missed the Group UDS requests - I will log another run tomo!

Thanks!

 

[Timmy_T6]

Hi @mmi

New log attached and even I can see there is something off here...

There are gaps in tme where we have marked the lamp flashing, also markers seem to be missing, and the record for lamp "on" isn't correct as it was flashing the whole way round the roundabout.

What does this mean, is this a time traveling bus??

Or perhaps a dodgy controller?

I am hoping once again you can help us

 

[mmi]

There are gaps in tme where we have marked the lamp flashing,

Yes indeed.

also markers seem to be missing, and the record for lamp "on" isn't correct as it was flashing the whole way round the roundabout.

I believe they are missing because they were lost in the gaps. VCDS obviously uses incoming data as "clock" also for markers, and if the data is missing also the markers during the gap are missing.

Or perhaps a dodgy controller?

Well, did some comparison with logs of my van (same ABS) and surprise, surprise - using grouped UDS requests mine does similar gaps every now and then. So I'd like to conclude the gaps alone do not indicate controller being faulty.

The grouped UDS request is special mode to speed up data collection, and obviously the ABS can't fully cope with that. Possibly the controller just gets too busy and drops less important tasks to keep up wit it's main task

FWIW checked same wheel speed data also in logs of Haldex controller, and it never had any gaps.

Or perhaps a dodgy controller?

All the above leaves us with controller's internal acceleration/rotation sensors as suspects. Unfortunately we obviously miss crucial data because of the gaps coinciding with traction control light.

So if you are still interested to provide data we should log the acceleration sensors etc. (the data items of post #5) WITHOUT grouped UDS. Could then try to do math to see if there is any discrepancy between e.g. steering angle, speed, rotation rate, and lateral/longitudinal accelerations

I have discussed the situation on other forums

Yes, have kept eye on that the van had logged acceleration sensor failures prior to the issue...

 

[Timmy_T6]

The fault is fixed!

Fitted new controller from vw to finally cure the issue.

In case of use for someone in the future:

Part numbers on my van:
7E0907379P
7E0907379M
New Controller part number from VW: 7E0907375P

The rebuilt one had a code I could not clear and after spending weekend trying to resolve I gave up and took van to vw (with old controller refitted).
Returned the refurb for refund.

VW couldn't diagnose the issue but said they suspect controller, so I bought a new controller and fitted myself today hoping it would work, thankfully it did!

Anyone reading this with a similar fault, do yourself a favour and just fit a new controller

Thank you @mmi for the help!