TPMS accuracy




I then compared with my 2010 E350. Noticed the same thing. I check TP with gauges about every couple of months and have never noticed this disparity before in E. Always check when cold.
Tried driving both vehicles and then checking TP's. Pretty much same results.
Current temps. are in upper 40's but I had kept gauges inside before checking.
Is it normal to have this much disparity? Is it possibly due to temps?
I then compared with my 2010 E350. Noticed the same thing. I check TP with gauges about every couple of months and have never noticed this disparity before in E. Always check when cold.
Tried driving both vehicles and then checking TP's. Pretty much same results.
Current temps. are in upper 40's but I had kept gauges inside before checking.
Is it normal to have this much disparity? Is it possibly due to temps?
The digital gauges I have do say they have a margin of error of +/- 1lb so really they could all be the same ball park.


I have a racing digital gauge which is stated for .1 psi with .5% accuracy (1/2 of 1%). http://www.longacreracing.com/produc...Gauge+0-60+psi
I find that when setting the air pressure to the desired level, the TPMS is usually off by 1-3LB between sides, since front to back is set for a different level.
This is when checking cold tires right after starting to drive on the display. When the tires are quite warmed up (40-60 miles later), the reading usually are equal per or only 1lb different between sides. If I check the tire pressure upon arriving home, the PSI are within .1 -.3lbs if not equal each side per the gauge.
I do not believe that anyone ever filled the tires up with nitrogen either for a difference of reading between cold and hot temps considering expansion rates between the gases or the possibility of slight amount of water in the tires induced by putting air into them.
Is this a real issue, not now that I would trust my gauge (same reading for other digital gauges I have) more than the TPMS sensor readings. Still close enough to let me know if there is an issue with a loss of air.








As long as I know this it is fine.
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My 2014 E350 has one monitor that reads 2 psi high. I know where it is (LF presently) and compensate accordingly.
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