TLF on DPM - The Ultimate Guide

[Belgarion]

Well I went out again this evening and took the car along the same route but this time in sport mode. I was following an Astra estate around a windy section and could feel the system taking control again. Was not as bad as in touring mode but it felt as though either the brakes were dabbing on and off or the throttle on and off. Could definitely feel a jerky motion for a short time. Was travelling at about 60MPH.

I've also noticed that on sweeping bends the front end feels particularly light, certainly compared to my 111R, the Elise inspired more confidence.

So I'm not sure if its behaving as it should and I'm just not used to the car or if there is actually something amiss. Will have to call the guy I purchased it from who has a lot of experience with these cars and see what he says.

 

[Day1zero]

Many thanks - top write up!!

[Belgarion]

It's a while ago since I posted about concerns I had over the DPM system on my 350 sport potentially operating early. I had noticed some improvements after I had the geometry aligned at centre gravity, in the future I'll post the old and new settings. The car certainly feels more stable and is not trying to throw me into the nearest hedge on some B roads, and I had not noticed the DPM cutting in until recently.

I always drive in sport mode and a few days ago I felt the ESP cutting in, it feels as though the brakes are pulsing and the throttle is being reduced, this is whilst entering and during the bend, I'm not at any point accelerating out of the bend. This happened when following a transit van so I was a bit surprised as my understanding was that the system should not activate unless the car was on the verge of breaking traction, I find it hard to believe the Exige is about to break traction before a transit van.

Lotus Silverstone plugged it in and said there were no fault codes detected.

So I thought I would try to open this up again to see what experiences other people have had and if what I'm experiencing seems correct. 

Thanks

[DH2]

Any deviations from standard on the car?

Definitely got the correct dimension tyres?

Have seen incorrectly set steering angle sensor cause issues.

Ideally need to log some data when the problem occurs. 

[Belgarion]

Only 2 deviations from standard, it has an Alias 23 induction kit and the rear tires are Pirelli P zero's, not corsa which where on the car when I bought it.

The Front tires are Michelin PS 4's which I had fitted in May this year, all tires are standard size.

Is there a way I'm able to log data? Lotus where not able to find any reported faults, but I assume if there was a wrong setting on a sensor it may not necessarily show as a fault.

[DH2]

15 hours ago, Belgarion said:

Is there a way I'm able to log data? Lotus where not able to find any reported faults, but I assume if there was a wrong setting on a sensor it may not necessarily show as a fault.

No, only your friendly Lotus dealer can do this.  As you say, just because there is no code, does not necessarily mean no fault.

Dave

[Belgarion]

Ok thanks Dave, next time I'll record when it happens and see if they can pull the data off. Interestingly it has happened on the same stretch of road twice so do wonder if its something to do with the surface although it does not feel unduly rough. Also happened coming onto a  sweeping slip road when I dont think I was near the limit. I'll ask Silverstone next time I'm in if they are able to check the steering angle sensor.

Appreciate your help

[DH2]

The ABS system does not record any data, so you need to log live data.

Dave

[Belgarion]

Ahh ok.

I'll probably just ask them to re-calibrate the steering sensor. The car had been sitting in a garage uncharged for quite a period of time before I purchased it, its always possible something went amiss with the battery going flat for so long.

Worth a try

Simon

[DH2]

Also check that the the drive peg for the steering angle sensor is correctly located.  This would also present itself with observation of the steering angle data - the sensor is very sensitive to any movement of the steering wheel, if there is a dead spot before the angle changes, the peg may be incorrect.  Have seen this on a couple of cars.

Dave

[Belgarion]

Ok that's interesting, I'll look into that as well then.

Simon

[Belgarion]

Is this the peg alignment you are referring to?

 

 

[DH2]

3 minutes ago, Belgarion said:

Is this the peg alignment you are referring to?

 

Correct.  You can check it by assuming the position, head down in the footwell!

As per that thread, there is a small tolerance in the calibration, but if you have to move the peg/sensor relationship, you will need to recalibrate (which takes seconds, but does need dealer diagnostics).

Dave

[Belgarion]

Perfect, thank you Dave, head down footwell this weekend it is then.

Glad I've been loosing weight, I might fit now.

Simon

[Belgarion]

Hi Dave

I know its not strictly in the spirit of Lotus ownership, but there was no way I was going to be able to get my head down in the footwell so I had to cheat. Managed to take some pictures and I think you may be correct, it looks to me as though the sensor is 180 degrees from where it should be. The picture on the left is an image from the service manual showing the correct orientation and the other pictures are of mine. The middle picture shows the slot empty where the peg really should be. The two pictures on the right I think are showing the peg in the wrong position. Was really difficult to keep the phone steady so they are not that clear. But I think the middle one pretty clearly shows no peg.

Does this look incorrect to you??

Appreciate your help with this

Simon

 

[Belgarion]

I;ve brightened the picture up a bit so the peg location is a bit clearer.

 

[DH2]

Agreed, it looks like it is in the opposite position.  This might be enough to upset the DPM, but no promises!  Certainly worth setting it correctly and recalibrating the sensor.

Dave

[Belgarion]

Thanks Dave

Will have that looked at and report back.

Thanks for the help

Simon

[Belgarion]

Hi Dave

Bit of an update, Lotus Silverstone have confirmed the SAS was 180 degree out of position. They have corrected the orientation and recalibrated it, I pick it up tomorrow. Probably won't know until later next year if it's fixed the problem as the weather is getting worse now and I won't be planning to throw it about until it gets warmer. 

Will update again when I get a chance to push it a bit.

Thanks for the advise, there is a chance this could have contributed to issues with the ESC.

Simon

[Rolf]

Had also strange behaviour of the DPM system, caused first by a minimal steering play from a bad u-joint. 
Symptom: Accelerating on the Autobahn for overtaking at 100 mph it went in limp mode on the left lane. No fun reaching for the breakdown lane while rolling out...
After several restarts the yellow TC light followed by the yellow spanner symbol disappeared, car ran fine on the defensive 2 hours drive home. No codes in the system could be found!

During the steering column lower u-joint exchange the garage misplaced the pin of the steering angle sensor which can be seen in the video.  No problems on the  60miles drive home from the garage, but strange claq claq sound when steering at low speed into the garage. Claq-claq sound at certain steering angels can be heard in the linked video.

 

 

[Belgarion]

Still waiting for some decent weather conditions to see if my problem is resolved, looks like that may be quite some time away.