Speedo adjustment
Mountain Pass
Joined: Jun 2010
Posts: 185
Likes: 3
From: Scenic Vermont
Not sure that I'm following you. The size is in the spreadsheet. You change the end of the second octet to 4C from 00 in order to change the speedo to a 285/75R18...which just so happens to be almost exactly the same size as a 35" (34.81" or 4 revolutions per mile off) tire. Its dead on with GPS for me. If you want another size you have to find the hex value to get it. Anything larger than that 285/75 though will throw a CEL.
Speedometer Recalibration for Different Tire Size
BCM 726-12-01 xxxx xx00 xxxx --> xxxx xx4C xxxx
Forum comment: "Original tire size 275/70r18, New size 285/75r18. No DTC codes after 900 miles. This is a small change. Larger tire size changes do calibrate the speedometer but a check engine light will persist."
Speedometer Recalibration for Different Tire Size
BCM 726-12-01 xxxx xx00 xxxx --> xxxx xx4C xxxx
Forum comment: "Original tire size 275/70r18, New size 285/75r18. No DTC codes after 900 miles. This is a small change. Larger tire size changes do calibrate the speedometer but a check engine light will persist."
https://www.ford-trucks.com/forums/n...ply&p=17582784
Its Comin Right for us!
Joined: Feb 2005
Posts: 12,219
Likes: 2,674
From: GA
its going to be temping to go back up when i do 37's and just deal with a cel . The he code works really well and it only took a few drives to come to my final value posted. I will probably wind up just rolling with a cel to have an accurate speedo
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Superduty.pride
1987 - 1996 F150 & Larger F-Series Trucks
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Oct 14, 2011 07:11 PM
