Tire with ! symbol lights up after 80MPH over 10 minutes

[X5rolls]

Originally Posted by sckooby94

Fill up your tires with nitrogen and you wont have this problem anymore. Nitrogen improves the life of your tires and doesnt require refills.

This isn't about low tire pressure.

[X5rolls]

Originally Posted by Proflyer

^ that's not true at all. Nitrogen is the biggest scam I think to hit the auto world lately. I hope everyone remembers that atmospheric air is about 78% nitrogen anyway...the only thing the nitrogen does is it is less temperature sensitive, but that's hardly an issue with passenger cars. Race cars/race motorcycles are a bit different but still, not a big deal. Also they use it in airplane tires (when they can) because of the huge temp swings.

If your tires leak at all or the valves leak at all (whcih is normal, you generally need to add air every few months) the nitrogen won't change that a bit. Instead, you'll just be paying $10/tire to fill them and then people think they need to 'change' the air if they can't get nitrogen.

Back to OP, obviously check air pressure, but speed and time will increase pressure, not decrease it, so that doesn't make a lot of sense. Only other thing I can think of is maybe the battery is going bad and at speed the sensor has a harder time reading it? Is the system wheel specific? If so, try a quick rotate and see if the issue moves. If not, then it's more likely an issue with that sensor in the wheel well.

The light in the 06 X5 is not wheel specific.

[StephenVA]

As you may know the light is driven off the speed sensors (34526771704 DSC PULSE GENERATOR- FRONT, 34526771705 PULSE GENERATOR - DSC REAR (from 10/03) one per wheel hub.
If the fault keeps coming back try pulling it loose (both ends) and cleaning it as it could be one is loosing it's signal due to age, dirt, poor connection, or just getting weak.
The above is one SUGGESTED approach to the issue. The other would be to reset (re-learn) the tire monitor system a few times to the tire's (hight).

My own 4.8is did the same thing. Only on trips beyond 30 miles at speeds above 65. Reset twice issue resolved.

Your experiences maybe the same or ....

[X5rolls]

Yes, it could be the tire sensor (this vehicle does not use TPMS but determines the tire revs and equates this to pressure. This could be more serious as a potential wheel speed sensor could effect operation of ABS & DSC - they both use wheel speed sensor to determine if they are needed to come on to aid the driver in keeping control.

Regardless, the tire pressure is still the same (I've checked) in all 4 tires and only recently has it started to light up. I check tire pressure pretty frequently and think that's not the issue.

My SA will have the tech use the BMW service computer on Friday to check for codes and see what the situation is.

Thanks for the reply.

Originally Posted by StephenVA

Answer:
The vehicle uses speed sensors to read tire revs. At higher speeds the difference between 2-3 psi right versus left tire, front versus rear tires will trigger the alert. Lower speeds may not trigger the delta difference. Warm tires expand, colder tires do not.

Double check the tires, make sure they are within 1 PSI of each other, reset the tire alert system, and drive. The proceedure is on the forum in multiple postings. Also in the owners manual. My took two attempts at resets.
Edit: Check tires first thing in the AM when they are STONE COLD.

Tire Rack tire pressure info - more that you would want to know. http://www.tirerack.com/tires/tirete...141110170219:s

In my experince, the system on the 4.8is (big tires) is more susceptible to alert triggers on small psi differences between the tires.

Buy a professional tire gauge (0-60 psi) instead of a pencil gauge that uses friction vs psi to display PSI. I have all the above and see a 1-2 psi difference between new.
Suggestions: http://www.summitracing.com/search/p...-and-inflators
Intercomp Racing 360060 - Intercomp Racing Glow Tire Pressure Gauges



I am an analog visual, so this is what I have. Others like digital...

Now back to the discussion on what air mix is inside the tires......

[X5rolls]

Originally Posted by StephenVA

As you may know the light is driven off the speed sensors (34526771704 DSC PULSE GENERATOR- FRONT, 34526771705 PULSE GENERATOR - DSC REAR (from 10/03) one per wheel hub.
If the fault keeps coming back try pulling it loose (both ends) and cleaning it as it could be one is loosing it's signal due to age, dirt, poor connection, or just getting weak.
The above is one SUGGESTED approach to the issue. The other would be to reset (re-learn) the tire monitor system a few times to the tire's (hight).

My own 4.8is did the same thing. Only on trips beyond 30 miles at speeds above 65. Reset twice issue resolved.

Your experiences maybe the same or ....

Good ideas - thanks

[StephenVA]

My pleasure....

Good luck, as that light always makes me jump when it pops on.

[X5rolls]

Thanks -

When it first started happening it made me worry a bit - 75 mph + and the tire light goes on. Slow down and pull over. Then tire pressure checked out and light was off when I restarted.

After that I wasn't as concerned and now I expect it. Still, I don't want it going on and will get it fixed. First time though wasn't great times.

Originally Posted by StephenVA

My pleasure....

Good luck, as that light always makes me jump when it pops on.