Any way to make cruise control less aggressive?

Uwe said:

The thing is, some people are at least honest enough to tell their customers, "Hey, this is a Beta and may not work quite perfectly just yet!"

Click to expand...

Sure. Vendors who properly label their beta versus mature stuff -- like Ross-Tech -- are great. Vendors who sell garbage and expect their customers to test and debug it for them, not so much.

Jason

Dana said:

I don't know that engine but the part number (03L 906 023 DQ) resulted in a Workshop campaign 23F7 TPI (Recall, which would need to be checked by VIN at your local dealer) in addition to a whopping list of RoW specific TPIs for a huge list of issues.

Click to expand...

I did ask a couple of dealers today about this workshop campaign, both stated there were no outstanding recalls based on my VIN. This was definitely worth a try though...

Dana said:

Based on the scan this engine controller may be up to date..

Click to expand...

One dealer did say the ECU was up to date, the other said they wouldn't know without hooking it up. I am more inclined to believe the latter dealer, having said that they want money to hook it up even if there is no issue. If I can find it beforehand that an update is available and what it addresses, this may certainly be a viable option.

On a side note, I have noticed that very occasionally (say once a week or so), when starting the engine from cold the revs will dip down to 800rpm then blip up to 1200rpm and repeat for around 5 seconds then stabilise at around 850rpm. Not sure if this is relevant but thought worth mentioning.

Thanks for your help!

We had an interesting CCS issue in support last week with a 2006 (1K) Canadian / NAR market Jetta PD TDI with 02E DSG gearbox that was related to LF WSS values. The VSS would surge only with CCS enabled. That vehicle used the older Mk60 ESP and the technician resolved it by replacing the LF wheel bearing assembly so the WSS values were identical when traveling straight.

That may be completely off track for this vehicle but .. I would make sure all 4 WSS values are identical. If you have one that is suspicious I would unplug it (resulting in new faults) and see if the CCS behavior is identical or not.

Dana said:

We had an interesting CCS issue in support last week with a 2006 (1K) Canadian / NAR market Jetta PD TDI with 02E DSG gearbox that was related to LF WSS values. The VSS would surge only with CCS enabled. That vehicle used the older Mk60 ESP and the technician resolved it by replacing the LF wheel bearing assembly so the WSS values were identical when traveling straight.

That may be completely off track for this vehicle but .. I would make sure all 4 WSS values are identical. If you have one that is suspicious I would unplug it (resulting in new faults) and see if the CCS behavior is identical or not.

Click to expand...

Interesting information. I have been focusing on the Wheel Speed Sensors until recently and the rears were out by 1km/h pretty constantly. The front left vs front right was often out by 1km/h as mentioned earlier on in the thread. It would be appreciated if you could perhaps make a log from measuring block 1 of the ABS module so I can check for comparison against another vw vehicle and eliminate the speed aspect totally. Thanks.

I contacted another dealer today as I have been receiving conflicting information from dealers down here on whether updates are available for the ECU. This one said the current software version is 9771 vs 9638 which I am on now. They didn't know what bugs were fixed but this is more hopeful than the other dealers I contacted. I plan to get the update done out of warranty with them soon. I hope it will fix the problem, if it doesn't at least it's another I can cross off the list !

Thanks.

I don't think 1km/h is going to cause that but... my current vehicles are limited to a 2002 Mk60 Non ESP (ASR only with manual trans) 1.8T Gti and a 2012 Tiguan (with Passat 3C type ABS and silly EPB system). The Tech Support crew is on-site this week so we have a 2012 NMS Passat Tdi and 2012 Golf R 2.0T with MK60EC1 so I'm sure we can baseline a known good car or two.

That dealer trip sounds like a plan. Even if the dealer cannot update the software again they can plug in the SVM code and give it a shot.

Hi Dana,

Am I right in thinking the SVM code 32EA is particular to my engine part number, and from this being entered in the VAS application it searches a database in Germany for any newer updates? Is it worth me mentioning this prior to the tech hooking it up or only if he can't find an update by some other means? Just trying to figure out how it works.

Yes it would be great to get an abs speed sensor log from one of the techs cars when they're in the workshop. I will then compare with my own. Thanks Dana!

Hi again,

Here is a LINK to the raw data (in csv format) of my ABS sensors through various speeds. It would be great for a comparison from someone else's vehicle. Thanks.

Slight update, I had the software on the Engine Controller updated today.

Upon checking the version using VCDS, it has been updated from 9638 to 9970. The dealer was unsure as to what the update actually fixes. Unfortunately I am still getting the regular jerking cruise control at lower speeds (<60mph) every couple of seconds or so. So I think I can eliminate it being a software issue now. To re-confirm, there are no fault codes in any module.

If it's not the speed sensors, I wonder if the issue could be the Dual Mass Flywheel or the EGR causing the issue. I suspect if it's the latter, I would have the issue with the cruise control off when maintaining a steady speed as well? I mention the DMF because I have a clattering noise from the engine area on idle tick-over, I suspect this is due to worn springs in that assembly causing some play.

Lastly, is there any particular parameters that I can measure to check the actual load on the engine or demand fuel flow. Then I can see the source of the jerking motion virtually and see whether this is linked up to any difference in another parameter at that time. There are lots of parameters I can monitor in Advanced Measuring blocks in the ECU but I am really not sure which would show the demand or fuel flow etc... Thanks.

Thanks.

Hi Adam:

Just a shot in the dark here, but: I wonder if the root cause of the problem is that the 1.6 liter engine in your car is working 'relatively hard' to maintain the lower speeds (speeds below 60 MPH) when you have the cruise control engaged, and as a result, the engine is a bit sluggish to respond to small amounts of increased fuel flow, and as a result, the ECU sends a bigger squirt of increased fuel flow (as a second attempt, so to speak) when the car does not begin to recapture the target speed fast enough after the first small amount of increased fuel is provided in response to the drop in vehicle speed.

I suspect that VW has rigged the ECU and the transmission in such a way as to maximize fuel economy when cruising at steady speeds below 60 MPH. The transmission is probably in the highest possible gear, which means that the engine is turning quite slowly (slowly relative to a more typical freeway speed of 70 or 75 MPH). At that slower engine speed, the engine is likely not operating at optimum speed for producing torque, or horsepower, or whatever is needed to quickly increase the vehicle speed when just a small increase in fuel flow is scheduled. Consequently, the cruise control system schedules another, more substantial increase in fuel flow to correct the slower than set-point vehicle speed, and it is that second bump-up in fuel flow that you are feeling.

My VW has a 420 HP 6.0 litre 12 cylinder engine in it, and when the cruise control is engaged at lower vehicle speeds, it will very smoothly and very efficiently maintain the cruise control set-speed regardless of whatever hindrances it may encounter (hills, gusting headwinds, standing water, etc.). The only difference between my car and yours is that my VW has a large surplus of horsepower available and torque available when the engine is operating at slow speeds, and (perhaps) your car does not.

I've seen the same kind of behaviour with aircraft autothrottle systems - if you command a flight level change at a high weight on a hot day, you will feel a noticeable surge of power to maintain the set speed during the climb. But, at lower set speeds, lightly loaded, on a cold day, you hardly hear or feel anything when a FLCH is commanded.

Michael

Hi PanEuropean,

Thanks for your reply. It certainly makes me think a little more about the engine torque on my car. I can understand it having little in comparison to yours on the other end of the scale. You are indeed right in thinking that mine is purely made for economical driving and lower emissions. The higher gearing is very noticeable compared to my last car (a 2.0 140bhp model). However, I have asked on the forums about peoples experiences of the cruise control on my same model and the consensus has been that their cruise is smooth and progressive with no abrupt changes in load requested. My car pushes about 1500rpm at 50mph in 5th gear for comparison.

A concern that I have now is back to the EGR. Is there any way I can confirm that the EGR is definitely not to blame at all. Would the confirmation that the problem does not occur when the cruise is off (and no fault codes) be enough to eliminate the EGR?

Very interesting comparison with aircraft auto throttle systems. I have a keen interest in aviation and have never thought of a comparison with my cruise control against a B777 etc I like it though, I will rename my engine GE90. Seriously though, I havent seen whether the cruise acts differently based on different temperature/pressures...open to anything at the moment so may explore this.

Again, if anyone can provide a log of their abs sensors through the speed range, that would be great. Then something else to cross off the list.

Thanks.

Just throwing another thing to check. At that mileage is it possible that the variable vanes are sticking on the Turbo and so causing some slight boost control issues, have you checked requested against actual boost when the problem occurs. May not be enough to throw over or under boost codes - but enough to hamper the ECUs fineness of control when on CC.