^^ The two minutes above 20mph is to extinguish the TPMS fault light once it has sensed a fault. Sensing a fault takes 20 minutes at a speed exceeding 20mph.

 

That doesn't sound correct. You could be dead in twenty minutes! a typical wheel speed sensors check how many times per second but a TPMS Safety item takes 20 minutes, that's incorrect or total BS! Just think about it.

EDIT: The '09 Workshop Manual states the TPMS signals are sent every sixty seconds when over 20mph.

 

There may be something to the 20 minutes. I currently have a flaw in the tpms system. Sometimes I get the tpms warning as soon as I start up the Escape, and sometimes it doesn't show up until I've driven for about 20 minutes. I haven't figured out what makes the difference.

 

I would go ~20 min on a cold start before the warning light and chime, but after the first restart after warm-up, I would get the warning right away.

I swapped my '05 tires and rims with my '09 Limited tires and rims for about a year. The '05 rims have no sensors, so I got the warning for a year on my '09 FEH. It was like clockwork to silence the warning chime every time until I put the stock rims back on.

Gary

 

I've done something similar. I bought a set of older Escape rims, perhaps '05's, for swapping winter/summer tire sets. The older set caused tpms errors because either there were no sensors, or they were the different (band) type. I did nothing and the errors stopped appearing after about 6 months. I then installed a set of Ford-compatible sensors from eBay for about $25 each, and got them working ok in the '05 rims. But then when wheel rotation time came around again, I put the original rims back on. The tpms errors appeared again because now it didn't recognize the original sensors. While sorting this out, my mechanic determined one of the original Ford sensors had gone bad. Rather than replace just one, he replaced all four original sensors, with EZ-Sensors, at a cost of almost $300. The programming of these involved someone making a mistake, so I'm still one step from sorting out all the tpms issues with my Escape and the two sets of rims.

This whole tpms thing must certainly have been a boost to the bottom line of the parts makers and service garages.

 

Tire pressure is always checked at cold inflation so your saying this safety mandated item is delayed till the tires may become warmer and pressure would be higher? That's has to be incorrect or the fact that you had no sensors present but you'd think that would trigger a fault anyway.

 

Probably only a Ford engineer could explain the logic behind the functioning of the TPMS warning light.

The main reason for fixing this stuff is so that you can use cruise control. I can understand why tpms errors would disable cruise control, but it adds to the nuisance factor.

 

Who mentioned that a TPMS disable cruise control? The first time I had a TPMS fault was on the highway and I continued to use cruise control.

 

Who said anything about warmer or tire pressure? The sensors were gone so it had to involve resetting the error over hours like overnight. Once the 20 minute error came up, I got the warning the rest of the day as soon as I started the FEH. If I had the sensors in, the low tire pressure should have went off if my tire was below ~25psi as soon as I turned the key on.

As far as CC, I never loss it with the error light or tire pressure warning message. I used CC in EV for a year with no issues. I think the real question is, if you get a warning of low tire pressure (which I never got), does that prevent CC? It could very well disable CC like xspirit pointed out.

Gary

 

Explain how or what you mean about a 20 minute error that reset itself overnight.

When I got a TPMS fault, it went on/off several times in a 125 mile trip, off on restart later that on the way home, back on within miles, off just before I got home. It was off for several week than back on again. Nothing about a 20 minute delay in my findings and never lost CC.