Tire Pressure Sensor Fault!
 

Hi everybody. I just put 305/55/20 Nitto Grapplers onto my truck. Driving down the road a few miles the sensor went on. It keeps goping on everytime I start my truck. It has only been 3 days now. I called the place that put the tires on (Big O Tires), and they said that because I went from a smaller tire to a larger tire, and thats what is causing it to go on. Has anybody heard of this? I think they broke one!

They are full of it. Did you put on new wheels? Did they Replace the valve stems? Or did they possibly damage one of the sensors when they changed the tires? Also what size and LR tire was on there before?
Problem could be a lot of things, just need more info.

I had the Stock 275/55/20 on it. I took the stock 20's off, and put new after market 20's on. They put he sensors onto the aftermarket wheels and had no problems. I also left the stock tires (275/55/20) on it, and had no problems. As soon as I put the new 305/55/20 Nittos on I started to have the problem. I think it might be that they set the tire pressure to the new tire, and not the door pressure that its programed to.

What is the max pressure on the tire? I see 2 different load range tires among the Terra Grapplers. LR E with a max of 65, and a P series XL with a max of 50. Neither one do you want to run at the pressure that is on the door. That would be too low as the OE tires would have used 35psi. Tire pressure has to be for the LR that you have. Once you go to OE tires that have a different load range, you cannot use the door sticker number. The LR E should be at 45, the P series XL about 40. Once you have the correct pressure in the tire, you will need to get the system reset. That can be done by buying a reset tool, or going to someone that has one, like the dealer. In my opinion, the reset tool is worth every penny, that it costs, about $25.

Thank for the help Kingfish51.
50 PSI cold for my new tires. They told me that they put all the tires at 50lbs all around. They also said that the spare tire was low, so they put air back into that one. The sensor is no longer coming on (so they say). I have not picked it back up yet, but I will let you know haow it goes.
also, wher would I pick up a reset tool?

You can get them off ebay, or at the Ford dealer.

50 is too high for those tires. That will do nothing but wear them out quicker. Run them at 40.
Putting them to 50 is probably what caused the TPMS to set an error. Even 40 probably would have.

I assume your spare is a 18", probably 275/65R18. I hope they did not put 50 in that as it is a max 35 or 44 tire.

OK I'll try ebay. thanks

So the max pressure cold is 65psi on these tires. You think that 50psi that they are set at now is to high?

The spare is an 18", iyt was set at 35psi.

The Tire pressure sensor fault did turn off for about 10 imles. Then it turned back on again. It looks like im going to have to re-learn the sensors with the on board comp. Any sugestions would be great.

I thought you stated it was a max of 50, not 65. If max is 50 set them to 40, if the max is 65 set them to 45.

Just use the reset tool. It will reset everything. If it keeps coming on after that, then there may be a bad sensor.

Changing tire size does not trip a sensor. Breaking one when putting new tires on does. Go back to the installer.

Low pressure or bad sensor = light on the dash. Either/Or.

I have sensors and reset tools if you need them. Please call me if I can help.

The sensors on the 09 up will set a fault when the pressure goes up or down a certain percentage. Having a reset tool makes it nice, especially in the winter when pressure will go down normally because of the cold. You would not want to add air just because of temp. Going from a tire with a recommended pressure of 35 to one that is higher will set the fault. Same if going to a lower recommended pressure.

Ok I set the tires at 45. Now im trying to track down a Reset tool.
Do you happen to know the part# for he 2009 F-150 Reset Tool?

Part number on mine is 8C2T-1A203-AB. It will work for 2010 also.

P.S. - Reset procedure is in the owners manual. Very easy and takes all of about 1 minute.

Got it thank you. Just ordered one off of ebay.

Thanks for your help. I'll let you know how it goes.

I have an 08 that my TPMS light came on.

Quick history:

I changed out to aftermarket wheels (18's) same size. They did not order new bands for the sensors therefore the sensors were mounted directly to the new wheels. 1 sensor fell off after about 3 months setting the fault. Now that all the sensors have been checked by Big O Tires computer they show they are all working and I have 50 PSI in my Nitto TG's. The computer shows one tire sensor is indicating it is off by 10 PSI but all 4 tires have 50 PSI.

So I have been living with my light on. If it was not so expensive I would buy 4 new bands and sensors to install.

Any other ideas?