Powershift data logs and P0715

rondeo · 09-06-2016, 10:51 AM

Quote:

Originally Posted by Mondaveo

Thanks, it is interesting to know. I have wondered why in FORScan there is only one GISS reading exposed on the TCM, given there are two shafts. I had thought it would allow me to see the raw values of what you say are in fact three sensors, but it doesn't. Presumably there's some aggregation going on to give the one GISS reading?

This can get a bit confusing.

Here's how I think it goes ATM:

Forscan has RPM, GISS, VSS.

The first speed sensor is detecting the engine output speed via the clutch housing. That's RPM. But in the P0715 description the words 'input shaft' are used, so a terminology issue.

The other two speed sensors are detecting the two gearbox input shaft speeds, which are driven by clutches 1 & 2. These are coaxial shafts.

There are also two gearbox output shafts, the ATSG manual shows input shaft 1 speed sensor being read 'via output shaft 2'. I suspect that might be Forscan's VSS, making GISS input shaft 2 speed (via output shaft 2). One of these shafts will be freewheeling depending on the gear selected.

So ATM I'd say P0715 refers to a fault in the RPM (aka 'input shaft') sensing system, the sensor for which is dangling in Manchu's photo.

Mondaveo · 09-06-2016, 12:43 PM

Quote:

Originally Posted by rondeo

This can get a bit confusing.

Here's how I think it goes ATM:

Forscan has RPM, GISS, VSS.

The first speed sensor is detecting the engine output speed via the clutch housing. That's RPM. But in the P0715 description the words 'input shaft' are used, so a terminology issue.

The other two speed sensors are detecting the two gearbox input shaft speeds, which are driven by clutches 1 & 2. These are coaxial shafts.

There are also two gearbox output shafts, the ATSG manual shows input shaft 1 speed sensor being read 'via output shaft 2'. I suspect that might be Forscan's VSS, making GISS input shaft 2 speed (via output shaft 2). One of these shafts will be freewheeling depending on the gear selected.

So ATM I'd say P0715 refers to a fault in the RPM (aka 'input shaft') sensing system, the sensor for which is dangling in Manchu's photo.

Ah, thank you my man! That changes the interpretation of my graphs and could be a breakthrough. If input sensor = "RPM" then I should see any evidence of the erratic signal on that line, rather than the line for "GISS" as I'd thought. And indeed I do have a squiggly trace for "RPM" in many instances where the gearbox shifted awkwardly. I had attributed that as a result of changing engine load with the clutch dis/engaging but it looks like it could be the evidence I was seeking.

The interesting thing now would be to compare the "RPM" exposed by the TCM with a recording of the actual RPM at the engine (ECU?). Unfortunately I don't think FORScan allows me to live stream from two different modules at once...

(BTW, I think you mean Bundy's photo?)

manchu · 09-06-2016, 02:27 PM

Quote:

Originally Posted by Mondaveo

(BTW, I think you mean Bundy's photo?)

definitely not my photo.

rondeo · 09-06-2016, 05:44 PM

Excuse me, Bundy's photo.

Also I wrote:

'There are also two gearbox output shafts, the ATSG manual shows input shaft 1 speed sensor being read 'via output shaft 2'. I suspect that might be Forscan's VSS, making GISS input shaft 2 speed (via output shaft 2). One of these shafts will be freewheeling depending on the gear selected.'

which should read:

'There are also two gearbox output shafts, the ATSG manual shows input shaft 1 speed sensor being read 'via output shaft 2'. I suspect that might be Forscan's VSS, making GISS input shaft 2 speed. One of these shafts will be freewheeling depending on the gear selected.'

There's a link in this German forum to a pdf which lists the engine speed sensor as a separate part:

http://forum.s-max-club.de/topic/651...haltvorgaenge/

The translation might raise a smile.

The fault could also be in the TCM. I think the only other sensor detecting engine rotation would be the crankshaft sensor, but don't know if it is used for anything else.

bundybear75 · 09-06-2016, 06:38 PM

Unfortunately your car seems to be showing the symptoms that mine did.

I didn't perservere with it - I only had a short window for a warranty claim and my symptoms came on quick and quite severe, almost to the point of being undriveable. After having it assessed at Phillip I struggled to get out of the Woden Valley with it grabbing neutral during changes at each set of lights I stopped at.

There is every possibility that the car was showing signs of it before it was sent to Pickles Auction.....

Good luck with it. I can recommend a good independent transmission center in Phillip if needed. They were great to deal with.

PS pretty sure it was my photo....

Mondaveo · 10-06-2016, 11:28 AM

Same symptoms as you, manchu, Groomy, Noelcbp here that were all confirmed...

Pretty sure it was a preexisting condition when this car was sold too. The last service docket includes a request to investigate a "hesitation" (nothing found, of course). And during the test drive, it grabbed neutral when I tried to accelerate up the Tuggeranong Parkway on-ramp. I didn't know at the time what that would portend...

The main thing I guess is that it seems not to have come on as severe as others have experienced. One loss of drive, and only occasional misses at shifting (though it's enough to make me tiptoe at every intersection I approach now). Maybe getting a bit worse now that the car is throwing codes, but ATM it's still drivable?...

manchu · 10-06-2016, 02:34 PM

Quote:

Originally Posted by Mondaveo

Pretty sure it was a preexisting condition when this car was sold too. The last service docket includes a request to investigate a "hesitation"

I'm sure mine was pre-existing too. The annoying thing is that the car was still (just) in warranty when it first occurred but instead of getting it fixed the owner just decided to make it someone else's problem. Lucky for me that someone was the dealer I bought it from.

Quote:

Originally Posted by Mondaveo

The main thing I guess is that it seems not to have come on as severe as others have experienced. One loss of drive, and only occasional misses at shifting (though it's enough to make me tiptoe at every intersection I approach now). Maybe getting a bit worse now that the car is throwing codes, but ATM it's still drivable?...

Yes it's drivable, but it could be very inconvenient or dangerous if you lose drive at the wrong moment.

I had the loss of drive only once in the first ~400km of my ownership so wasn't overly concerned because it sorted itself after a restart. The 2nd time it really crapped itself and left me stranded for hours. Thankfully it was within RACV towing allowance and wasn't with the mrs or kids.

It sounds to me like the issues are regular enough that you need to take action sooner rather than later. Consider also that if you need it fixed you may be waiting some time on parts. It took 1 month for my mechatronic unit to be replaced!

I'd be going straight to Ford for a diagnosis, report and quote for their recommended fix and check part stock. It might cost $150 odd to get this done but once informed you can start battling for it to be fixed for free or share costs under Aust. Consumer Law.

I really don't know how you'll go pulling the ACL card, especially seeing as you bought the car used, but it's worth a shot. A mate had an XR5 focus engine rebuild partly covered out of warranty and that car was bought used so there is some hope.

Highway cruser · 10-08-2020, 12:26 PM

Quote:

Originally Posted by Mondaveo

Ah, thank you my man! That changes the interpretation of my graphs and could be a breakthrough. If input sensor = "RPM" then I should see any evidence of the erratic signal on that line, rather than the line for "GISS" as I'd thought. And indeed I do have a squiggly trace for "RPM" in many instances where the gearbox shifted awkwardly. I had attributed that as a result of changing engine load with the clutch dis/engaging but it looks like it could be the evidence I was seeking.

The interesting thing now would be to compare the "RPM" exposed by the TCM with a recording of the actual RPM at the engine (ECU?). Unfortunately I don't think FORScan allows me to live stream from two different modules at once...

(BTW, I think you mean Bundy's photo?)

morning gents,

I've been having issues with harsh shifting for a long time and have followed this thread for almost as long. Having some time to spare at the moment I thought I would have a further look into the issue I'm having as it doesn't look like anyone has actually done a repair/fix on this yet, apart from sending to a gearbox specialist or selling the car, neither have I but I believe I have worked a few things out.

I'm getting P0715 basically all the time as well as the harsh shifting and jerking on take off, but have only ever had limited transmission function come up on the dash once.

On a slightly different note, what's everyone's thoughts about the chances of my issue being related to contamination on the GISS sensor?

From the graphs I believe the RPM line in the opening graphs will be coming from the bell housing that then plugs into the TCM. The GISS is a sensor in the mechatronic unit which can be referred to as the input speed shaft sensor. I'm pretty sure this is the sensor that I'm having problems with as well as Mondaveo had. This is based on the fact that when the car is stopped you can see on the graphs the value for the GISS goes to 0 RPM, meaning that both clutches are off and no drive is going to the gearbox. This is based on graphs I have taken.

Based on the fault code and the GISS sensor being in the mechatronic unit I believe that the reason that Mondaveo was quoted for coolant is that the mechatronic unit can be removed from the gearbox without taking the gearbox out, it does mean draining the coolant, hence the need for coolant on the quote. However the quote I believe shows the wrong sensor. based on the pictures of the part they quoted, this is the RPM sensor on the bell housing. At the moment I haven't tracked down the correct part number for the GISS.

It seems that the GISS sensor only reads input shaft 2. Based on both output shafts being connected to the main diff gear, both input shafts will be turning while either of the clutches or any forward gear is being used as the there's always a second gear selected. I can only assume that when its using a gear on input shaft 1 it works out the correct speed of input shaft 2 based on the gear ratio between the gear in use and the next selected gear.

I have tracked down a series of YouTube videos of the mechatronic unit being removed for a different issue, but it does show how to remove it, however not how to change the GISS sensor. link to the first video is here: https://www.youtube.com/watch?v=jxCEdxT2_Rk

I've also tracked down a manual for the 6DCT450, I've tried to attach to this post but it didn't work for some reason, but if you want a copy let me know.

It would be interesting to hear peoples thoughts on this.

Mondaveo · 11-08-2020, 10:10 PM

Quote:

Originally Posted by Highway cruser

I'm getting P0715 basically all the time as well as the harsh shifting and jerking on take off, but have only ever had limited transmission function come up on the dash once.

On a slightly different note, what's everyone's thoughts about the chances of my issue being related to contamination on the GISS sensor?

From the graphs I believe the RPM line in the opening graphs will be coming from the bell housing that then plugs into the TCM. The GISS is a sensor in the mechatronic unit which can be referred to as the input speed shaft sensor. I'm pretty sure this is the sensor that I'm having problems with as well as Mondaveo had.

The text associated with the P0715 code (at least that which I saw) was "Turbine/Input Shaft Speed Sensor A Circuit - Signal Erratic". I believe other sensors will get a different DTC number. So if you experience poor shifting behavior, and you have P0715, and you can observe implausible data coming from the sensor, then the fix is to replace that Sensor A.

Now there is conjecture about which is actually that "Sensor A", of the data sources exposed in FORScan I initially assumed it would be the one named "GISS", but out of the discussion on this forum it emerged it may actually be "RPM". The graphs I made did seem to show erratic readings coming on that RPM trace, but we never established definitively that this was the source nor which physical component it corresponds to. Anyway, I do know the Auto Torque techs who did the repair did also observe implausible data as part of their diagnosis procedure, whichever sensor that was.

When you say "no one has done a repair/fix", you mean as DIY? Because cars have been fixed, clearly, it has just required getting professionals to do the work.

I'm satisfied I've understood the fault and the repair even if not knowing all the details and nomenclature of the what and how. I'm pretty sure I read an article or saw some YouTube video or two about the disassembly and repair of the Getrag 6DCT to learn some details (e.g. I know there's special alignment tools required to put it back together), but I knew it was far too heavy a job for me to do personally so I stopped there. Are you planning to establish a procedure to DIY?

Austenite · 12-08-2020, 06:59 PM

Quote:

Originally Posted by Highway cruser

I'm getting P0715 basically all the time as well as the harsh shifting and jerking on take off...

I have tracked down a series of YouTube videos of the mechatronic unit being removed for a different issue, but it does show how to remove it, however not how to change the GISS sensor. link to the first video is here: https://www.youtube.com/watch?v=jxCEdxT2_Rk

Got super excited and thought you were on to something. In the technical manual it shows the imput speed sensor as reading the clutch drum housing, mated up to the flywheel. I think this is why the gearbox needs to come out to replace the sensor :(

However, if you could access the plug at the TCM using the method shown in the video, and somehow access the bell housing, might be possible to replace without removing gearbox?