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I did some googling on the U0422. I really can't seem to find any issues. It's looks like a communication thing.
So, I'm wondering if one module is programmed with my factory tire (17's) and the other is saying here's what we have (20's). Thus triggering the U0422.
Other than that, my speedometer is spot on and the tripO'meter is accurate as well. The MPG info is back to normal, the miles are correct, and the timer is correct. I haven't checked miles to empty, but i'm sure its correct as well.
Any version of Windows work?...We use apple crap (Ipads) in our house...I think we still have approximately 10+ yr old laptops, somewhere in the storage Black-Hole in our basement?
This is what I found in the repair manual for that particular DTC.
That DTC can be reported by different modules that communicate with BCM, your image appears to be from the RCM section. I found these in service manual:
So the new tire size BCM is reporting doesn't match the old size in PCM and throws the DTC. If only FORScan would let us access the PCM we'd be golden but only way around this for now is aftermarket speedo calibrator unless you want to live with the DTC.
So we've finally figured out how to correct speedometer error (if your truck is just off from the factory or you've changed tire sizes.) Thanks to solodogg on the mustang6g forum for figuring out where in the as-built data this info might be stored, even though I'm sure he'll give me all the credit for decoding the way Ford programs tire size in hex.
Good work on the spreadsheet and the work in reversing it.
Your calcs work out slightly wrong for Ford vehicles we have in Australia.
I have changed your 96.7% value to 96.75%. This now shows the calc is 100% matching all tire types and sizes.
255/70 R16 = 0910
265/60 R18 = 0938
etc.
I have compared my changes to every tire size and options that come with our Ford Rangers and Everests and 96.75 is the go.
Not saying it is wrong for US vehicles but you may want to update the spreadsheet for different % options and give an option to display KPH.
On a side note 0938 is 2360 Dec ( Metric mm circumference ). The circumerence for a 265/65 R17 is 2437mm so not sure why there is a decrepancy in the asbuilt files anyway?
Cheers
Stewart
Last edited by saeb; 11-19-2016 at 07:51 AM.
Reason: add text
10-24-2016, 06:19 PM
