low tire pressure light


  #1  
Old 11-28-10, 01:34 PM
M
Forum Topic Moderator
Thread Starter
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,076
Received 398 Votes on 354 Posts
low tire pressure light

My 2010 jeep wrangler has the low tire pressure idiot light. Yesterday the light came on. While the air pressure has lowered slightly due to the cold weather [currently at 32-33 psi, normally 35 psi]] I wouldn't think that would be enough to trigger the idiot light. I didn't have time yesterday morning to add air and have drove it about 40 miles or so.

Anyone know how those sensors work? Surely 2-3 pounds wouldn't set them off. I hate going back to the dealer but I'm not sure I have much choice
 
  #2  
Old 11-28-10, 01:55 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,964
Received 6 Votes on 6 Posts
Surely 2 - 3 lbs WILL set them off. My wife has them on her Dodge Caliber. Her LF has a pin hole leak that we can't find with soapy water and in a month the light will go on and it will be down 2 lbs. I'm going to have to take it to the tire dealer where we bought the tires to have him pull the tire off the rim and reseat it to see if it makes a difference.
 
  #3  
Old 11-28-10, 02:00 PM
Unclediezel's Avatar
Member
Join Date: Dec 2006
Location: Northeastern PA.
Posts: 2,230
Received 0 Votes on 0 Posts
Surely 2-3 pounds wouldn't set them off
Surprise surprise......Yes it will.....

AND.....MAKE SURE TO CHECK THE SPARE ALSO!!!!!!!

Your Jeep (Any Mopar after 2008 as well) is instant update, So there is NO reason to drive the vehicle after airing up. If tire pressures are corrected, and the light is still on.... You have a problem with the TPMS system. Any variation from your gauge to what the computer sees is likely your issue..... Pump em' all up to 38PSI and watch the lamp...if it goes off, then 1 at a time lower them 2psi at a time until they are as close to correct as possible without tripping the warning.
 
  #4  
Old 11-28-10, 02:18 PM
M
Forum Topic Moderator
Thread Starter
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,076
Received 398 Votes on 354 Posts
Thanks uncle

I remember reading in the owner's manual that you had to drive it awhile after reinflating the tire [s] The manual states that the light can't be used as a gauge because the tire would be getting close to dangerous low before the light would come on. It also said the spare wasn't affected unless it was on the ground..... but the spare had 33 psi before I aired them all up to 35psi. Good point about the gauge, I'll pump them up tomorrow and see how it goes. Thanks for letting me know you don't have to drive awhile before you can tell if that fixed the problem.

I just figured the light was useless because it wouldn't come on until the tire was 10 or more lbs low...... and I can feel less than that low behind the wheel. Never thought it would be just 2-3 lbs. Thanks again
 
  #5  
Old 11-28-10, 04:23 PM
Unclediezel's Avatar
Member
Join Date: Dec 2006
Location: Northeastern PA.
Posts: 2,230
Received 0 Votes on 0 Posts
In service area terms, there are 2 points here.....

One is "Threshold". which is when the warning lamp comes on, and "Hysterisis" which is basically Panic Mode, which causes the light to FLASH.

Hysterisis is usually caused by a defective sensor, but as an added bonus, the sensors do not register anything below 17 psi, which will make the computer think the offending sensor is inoperable..

The Spare tire is a 50/50 shot. If it has a TPMS sensor mounted to it, it most certainly is included in the loop, regardless of what position it sits in. This allows a "5 wheel rotation patttern" utilizing the spare tire during tire rotation.
We have all heard about the AWD vehicles and replacing tires as a set of 4??? If your road tires were to wear out and you got a flat , the spare would be "Unuseable" due to the difference in circumference of a "Fresh" tire.
Therefore, MFR's recommend using the spare in the rotation pattern.
 
  #6  
Old 11-29-10, 09:21 AM
M
Forum Topic Moderator
Thread Starter
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,076
Received 398 Votes on 354 Posts
I aired all 5 tires up to 38psi this morning but it didn't make any immediate difference. I did have trouble with one rear tire, the valve stem kept sticking open. I assume that might be related to the below freezing temps we had this morning. After several attempts of adding air, the needle seated.

I went ahead a lowered the pressure before I went to town and somewhere between 2-3 miles the light went off and has been off for the last 15-20 miles....... so hopefully that's the end of the tire pressure issue

Oh, the idiot light only flashed at start up, no flashing, just a solid light while driving down the road.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: