Changed tyre size in asbuilt and now p0825:00af

fred99999au · Sun Oct 27, 2019 9:20 pm

Hi all. First foray into the PX and making slight mods as I have larger tyres. I changed the tyre size as per viewtopic.php?f=12&t=214 .

Changed 0910 to 0977 in BCM 726-12-01 and today I now have a spanner after a while with a code of p0825:00af which seems to relate to a push pull switch for an auto based on some research.. Mine is a manual.

Doesn't seem to have any other effect than setting the code. Doesn't limp, still pulls like a train.

Doesn't make sense based on what I've seen, but after much messing with my PJ I understand that it is not always as it seems based on the terminology in the error message.

Anyone have an idea? I could put 0910 back and see if it changes the outcome I guess.

Wed Oct 30, 2019 8:24 pm

Where the asbuilt modules are selected, up the top run a PCM relearn and then clear the DTC and see if this resolves your issue.

If not you will need to drop lower than 0977 as by default an XL will top out before the 0977. Try 0970 other and see if that helps.

fred99999au · Thu Oct 31, 2019 8:48 am

Thanks Stewart. Will give it a try now that I have received my new cable from you. Will fix my ute laptop today and advise if there is any difference.

The spanner isn't always there, and clears by cycling the ignition. My ute is an XLS so hoping it is different to an XL.

Fireguard · Fri Nov 01, 2019 3:26 am

P0825 is a regular PX2 XLS Manual fault...... I've got a long winded story about it

, that fault seems to be restricted to XLS Manual cars with large tyre size adjustments, drop the correction size down a little and the fault will stop showing up... I'm still trying to figure out the upper limit for the correction, I'm down to small corrections - but haven't got there yet..

Out of curiosity, did the light come on just after doing a direction and gear change (ie, up shifting whilst coming out of a roundabout ?)

fred99999au · Fri Nov 01, 2019 10:48 am

Not sure. Seems random when it comes up. Cleared the codes and reset the modules but still coming up with the code. Will drop the size back and see how it goes.

Tyres on my ute are 265/75/16 MT ATZ.

Sat Nov 02, 2019 1:45 pm

Try a PCM relearn first but also change tyre size in the PCM.

fred99999au · Sat Nov 02, 2019 5:46 pm

Tried dropping the size in the BCM to 0970, and issue still present. How do I find the address in the PCM?

Sat Nov 02, 2019 7:28 pm

fred99999au wrote: ↑Sat Nov 02, 2019 5:46 pm Tried dropping the size in the BCM to 0970, and issue still present. How do I find the address in the PCM?

PCM 7E0-01-01 xxxx-5EA6-xxxx equals the BCM 0977 then run the PCM relearn, clear DTC and let me know if it resolves. Make sure to change BCM back to 0977 also.

fred99999au · Sun Nov 03, 2019 3:11 pm

No good I'm afraid. Changing the PCM also gave me a bonus DTC of Code: P1635 - Tyre/Axle Out of Acceptable Range alongside the original P0825 - Gear Lever Push/Pull Switch Circuit (Shift Anticipate). Also seemed to come up quicker. Another thing that I am not certain of but suspicious of is the odometer seems to be climbing rather rapidly.

For the moment, I have returned the stock values of 0910 in the BCM and 5AA0 in the PCM, cleared the codes, done module resets and a PCM relearn and taken it for a test drive. Seems back to where it was. Also did some live data monitoring whist test driving and monitored the VSS from the PCM vs speedo and GPS Speedo. Only thing I can conclude here is that nobody can stay at a steady speed in the west of Melbourne on a Sunday afternoon, despite 4 -5 lanes to choose from and that VSS is 4-5km/h under the indicated and GPS speed. Obviously from the larger rolling circumference of the tyres.

Which is what I was trying to modify for, the DTE values.

tugsay · Mon Nov 04, 2019 2:15 am

I have 2017 xlt manual shift and I changed the code to the exact number for my tyre size. 265/75/16. I don't remember the code now I should check it if you want me to find it.
I didn't use 977 because I thought that automatic transmission cars gives an error for the exact tyre size code and gave this opinion a try. It's been about maybe 3 months and so far so good, no errors, no dtc's...
When I'd check my speed with a gps speedo program on my phone I confirm thay my speedo shows 6 percent more than the gps. Gps shows 94kms and my speedo shows 100kms.

tugsay · Mon Nov 04, 2019 2:28 am

098A

This is the exact code for 265/75/16

markie90 · Wed Feb 05, 2020 6:26 pm

fred99999au wrote: ↑Sun Nov 03, 2019 3:11 pm No good I'm afraid. Changing the PCM also gave me a bonus DTC of Code: P1635 - Tyre/Axle Out of Acceptable Range alongside the original P0825 - Gear Lever Push/Pull Switch Circuit (Shift Anticipate). Also seemed to come up quicker. Another thing that I am not certain of but suspicious of is the odometer seems to be climbing rather rapidly.

For the moment, I have returned the stock values of 0910 in the BCM and 5AA0 in the PCM, cleared the codes, done module resets and a PCM relearn and taken it for a test drive. Seems back to where it was. Also did some live data monitoring whist test driving and monitored the VSS from the PCM vs speedo and GPS Speedo. Only thing I can conclude here is that nobody can stay at a steady speed in the west of Melbourne on a Sunday afternoon, despite 4 -5 lanes to choose from and that VSS is 4-5km/h under the indicated and GPS speed. Obviously from the larger rolling circumference of the tyres.

Which is what I was trying to modify for, the DTE values.

I was playing with Tyre Circumference in BCM, changed it for 285/75/16 (2619mm), Speedo was well out and P0825 Code came up once at speed, took it back to 2358mm and it's perfect for speedo. I've read it won't work for DTE though. Interesting thing that is only on our XLS's though

Sun Feb 09, 2020 6:37 pm

fred99999au wrote: ↑Sat Nov 02, 2019 5:46 pm Tried dropping the size in the BCM to 0970, and issue still present. How do I find the address in the PCM?

Keep going lower until you get a resolution, I have seen this before in XLS vehicles that originally had smaller tyre sizes to begin with.

markie90 · Sun Feb 09, 2020 6:46 pm

Hey Stewart,
Is the non-asbuilt function for tyre circumference effectively the same thing in asbuilt just different wording? Or will that not change dte and usage figures? Just want to make sure that if changing tyre circumference to line up with speedo accuracy actually makes odo and fuel usage more accurate also.

Cheers

Sun Feb 09, 2020 6:52 pm

non abuilt and asbuilt are the same and changing the same thing. Unless the tyre size is 100% correct in the transmission, PCM and BCM then your DTE, ODO and Speedo will not be correct.

If you line speedo up with GPS then ODO and DTE will be out by 4 to 5%.

I have everything in mine set to my exact tyre size now and DTE shows within .03 on my last fuel up, which is well below what the cluster can actually show.

markie90 · Sun Feb 09, 2020 7:02 pm

saeb wrote: ↑Sun Feb 09, 2020 6:52 pm non abuilt and asbuilt are the same and changing the same thing. Unless the tyre size is 100% correct in the transmission, PCM and BCM then your DTE, ODO and Speedo will not be correct.

If you line speedo up with GPS then ODO and DTE will be out by 4 to 5%.

I have everything in mine set to my exact tyre size now and DTE shows within .03 on my last fuel up, which is well below what the cluster can actually show.

Alright I think im on the right track then. In 'tyre circumference' i had to dial back the mm's to a fair bit below what the calculator gave me for 285/70/16's, but it got the speedo close to perfect. So i am on the right track, from here I'd have to ensure the value in pcm and bcm are the same (i think ive only done this in bcm) and also in transmission? I have a manual so unsure if this is the same as autos.

Thanks for your help as always!