I haven't driven with the donut spare in use, but according to the manual ('06 page 189) "when your temporary spare is installed, the TPMS will continue to identify an issue....". I interpret that to mean the donut doesn't have a sender and the TPMS will cause a warning with the spare in use.

When I swapped in my new full sized spare, I stored the removed wheel away from the vehicle, so at no time where there more than four wheels and a donut spare on the vehicle.

I really think I have a faulty TPMS sender and I'm going to mount the suspect wheel back on the FEH within the week. But thanks for the good ideas and I'll let you know what develops.

 

Cany anyone confirm the 2008 16" is the same size as previous years? IE as in bolt pattern and similar width. I want a full size spare, but not ready to shell out over $300 from a dealer for one.

 

UPDATE: I put the suspect wheel back on the vehicle (RR) and the TPMS warning did not occur during the last several hundred miles. But it did occur today about 20 miles into a freeway trip. I stopped by the dealer on the way home so they could capture the fault code, and ended up spending several hours there as they tried to figure this out. Anyway, after the service writer called the Ford "Technical Hotline", I did get some useful information, but no solution yet.

Here's what I learned that might be useful to someone. But remember that I don't personally know any of this to be accurate:

1) The low pressure trip point at which the warning illuminates is supposed to be 29 to 32 psi.

2) The onboard computer stores the location of the tire reporting low pressure, and also the temperature of the tire.

3) The system has to be "retrained" if a tire is moved or tires rotated, but they are unclear as to how this is to be done. (My belief is that it must be automatic and not require a technician to do anything)

4) A drive time of over 20 minutes at a speed exceeding 20mph is required for the system to read data from the tires. (I believe this to be true as it explains why I never get a TPMS warning in city driving, but always get it about 20 minutes into a freeway trip)

That's it. I'm supposed to try to get the problem to reoccur over the weekend and bring the vehicle in Monday to see if they can read the codes.

 

Don, thanks for the update.

I also went into the dealer for an oil change and asked them to look into that. They came back and said that the tire pressures were off and that's why I get intermittent sensor triggering. BUT, I have all four tires at 41psi!!

Unless the sensors triggers on over-pressures as well as under-pressures, I think the dealer didnt know what they are talking about.

Your point 4 seems to jive with when I see it triggers...usually somewhat into a freeway trip. I'll have try and keep track next time I'm on the freeway.

 

That's the same story my dealer gave me on my first visit with this problem, that the sensors check pressure differential and that all tires must be within 2 lbs of each other. They have since backed off that idea.

The other annoying (and ignorant) thing they insist on doing is lowering the tire pressure to 35 psi and telling me that 40psi is too high.

You aren't by any chance going to Barber Ford in Ventura are you?

 

My tires pressures have always been 40-41psi. But I had also had 41psi in all four tires BEFORE I bought the full size spare, and the extra sensor for it. I never had the sensor go off until the installation of the full size spare.

They actually didnt touch my tire pressures here....interesting...does that mean they knows and understand hybrid owners, or they are just not as "diligent" as yours?

I go to Heritage Lincoln/Mercury Dealer down here in Irvine/Tustin. They're a decent outfit...very professional, but on occasion they miss a few things.

 

Probably just not as diligent. I just got my oil changed at my dealership last week. When I told the service advisor I keep 42lbs in the tires I might as well have told him we didn't land on the moon from the look on his face. And of course, when I got the car back I pulled out the gauge and they were all back to 35.

 

I did a freeway trip today of more than 30 minutes and the TPMS warning never came on. That would seem to indicate that "retraining" the system last Friday at the Ford dealer has fixed the problem.

But it's hard to believe that I would have to have the dealership retrain the system every time I rotate the tires.

One possibility is that the system has to be initially "trained" so that it knows what TPMS sensor ID's are present from the factory. If another sensor is introduced, as in adding a full sized spare, then "training" of the system is again required to make it accept that sensor ID.

I'm going back to the dealer tomorrow and try to get an answer to all this. It's discouraging that the Ford techs don't understand this system at all.

 

If you have a full sized spare with a TPMS I believe thats the issue. From what I understood the system recognizes four tireID's from the four sensors on the wheels. They only transmitt when the wheel is turning I think. In any case when you rotate your 5 tires, ONE of the ID's is booted out of the memory and replaced with your spare.... The system needs to be retrained to recognize the four tires NOW on the axels and you are going to have to retrain the tires every time you rotate that fifth tire in.

I suspect that is the explanation for what you are observing.

 

That makes sense, but how did you find this out when my Ford tech isn't aware of it? And how is the retraining accomplished? On some of the Ford trucks the customer is given a special key fob to retrain the TPMS, but not on the Escape.

So it sounds like I'll be getting the TPMS warning when the spare is rotated in, which would be for 40k miles to go through all four locations. There's got to be a better way.