I recently added a full size spare to my FEH, new (matching) tire, used rim, and new TPMS sender from local Ford dealer. I swapped my new wheel/tire for the right-rear wheel/tire, as that's how I intended to start the rotation pattern. I left the donut spare as the spare tire for what follows.

As expected, I initially got a "low tire pressure" warning indicator for the first few miles. Then the warning mostly stayed off, but would ocassionally illuminate while driving. For the past several hundred miles it has been completely absent, and I assumed the system had accepted the new TPMS sender and all would be well now.

So today I got the warning while city driving, and it now comes on everytime I start the engine. It's been exactly 3 weeks and 1000 miles since I mounted the tire.

Any ideas on what's going wrong here and how to correct it? Could I have gotten a defective TPMS sender from the dealer? I guess I could put the old wheel back and see how that behaves. Obviously, I've checked tire pressure, and low pressure is not the cause of this problem. Thanks for any help.

 

Put the old one back on and see if it goes away. They should have a tool to check the TPMS sensor to see if it is outputing correctly.

 

I did exactly what you did, and got the same problems. At first, I thought it was just getting the id or address or something. Early on, it trips often (there's a thread about this). But then after a while of staying off, I would get a sensor trigger. This has gone on and off for the last 4-5 months...I didnt notice the durations (I'll keep track starting the next time it goes on). Since it doesnt happen often, I didnt mind it.

I'm now wondering if the sensor in the full-size spare is somehow causing the address/id to change from time to time, thus causing the computer to trip. Maybe the sensor is far enough not to trigger the computer, but close enough to just catch and confuse the computer a bit with this "extra" sensor.

 

In my case I still have the donut spare (no TPMS) in the spare tire well, so that's not what's causing my problem. I did read your thread and our problems do sound similar. I'm wondering if there isn't a "procedure" that has to be run to integrate the new wheel. Something involving the ignition key being turned while depressing the info button or the like.

I'll probably go to the dealer, play dumb, and see what they will do under warranty to fix the problem.

 

UPDATE: Shortly after my last post the warning stopped appearing. I then swapped the original wheel back, expecting to now get the TPMS warning since this would be a different sender. But no, no warning at all so far. Now I'm really confused.

 

Well, if it goes on again, keep us posted.

I'm going to get an oil change pretty soon here, and will get the dealer to check on mine. I'll post if anything interesting comes up with the dealer.

 

No warnings since putting the wheel back to the original position. I'll give it another week then swap the troublesome wheel back in. I asked the dealer about this, and the service advisor sent an e-mail to Ford asking for advice. They responded that I needed to bring the vehicle in while the warning was happening so they could read the trouble code. Don't know if my ScanGauge can help here or if the warnings are on a different data bus.

 

What was the reason behind this action? I've heard of people doing this on vehicles that see heavy off-road action. Is that why? Was there a specific reason or recommendation? Or just personal preference?

Apologies if the back story was already posted somewhere and I missed it.

 

I assume you are asking why I went with a full sized spare tire.

I've always had full sized spares, and decided I wanted one with the FEH since I often travel to remote locations on rough roads. With that thought in mind, I came across a great deal on an OEM rim, and the tire itself wasn't too expensive. The TPMS sender was the single most expensive part. I'm planning to rotate the spare so that will extend the life of the full set of tires. When I removed the donut spare and saw that the rim was full of mud due to the rim design, that really made me happy with my decision to go full sized.

 

Are you sure the donut doesn't have a sender in it.....I'm thinking it does. Could the 6 wheels be causing the confusion???

I swapped out all 4 wheels for mounted studs with the TPMS in the spare set. Got the warning on the way home (with 9 tires in/on the car), and the next day. Not again, and not when I switched to summer tires (which I did at home, so it did not have any time when all of them were in the car again).