Tyre pressure reset failure

[Paulfromfrance]

Hi there!
I come here to expose a problem that nobody around me was able to solve until now. Here is the context :

I own a 4.8is from 2005 which used to work perfectly until I had a small accident.
I bumped a curb and damaged :
- my front left rim
- the ride height sensor
- a lower arm was folded
- Steering rod broken

I did the following things:
- rim repairing
- ride height sensor replaced
- wheel bearing replaced
- lower arms replaced
- steering rod replaced
- 4 new ABS sensors
- New geometry

But since:
- It drives normally but every each 40 miles approximately, my tire pressure warning lights in yellow. Then I stop the engine, restart it and do the reset procedure by pressing the tyre pressure button for severals seconds (as described in maintenance book, and as I was used to do successfully before the accident) but since nothing happens : the warning light stays.
- If I wait for approximately 30 seconds before restarting the engine, the warning light disappears at engine start… (but reappears 40 miles later).

My concern is that I fear to damage something in my car (differentials, transfer box, or gearbox) if keeping driving with this failure.

Additional clues :
- My X5 has NO pressure sensors in the wheels. It detects possible pressure failures by comparing each wheels turns.
- I checked many times my tyres pressure, they are perfect.
- I tried to mount my winter wheels to exclude my summer wheels as a cause, the problem is exactly the same.
- The reset button itself works, because when keeping pressing it before starting, it lights the tyre pressure symbol in yellow, then in red, before disappearing. But the reset procedure fails as described before.
- It seems that when I drive under 60 mph the warning doesn't light. I already drove several times for 100 miles approximately on small limited roads without having the warning signal. But on highways at 80 mph (French limitation), which represent 90% of my trips, the warning lights EACH TIME after +/- 40 miles.

As said before, no mechanical around me is able to solve it, and have even absolutely no idea about a possible cause, that's why I came to your community which seems to be very wise regarding tricky problems. So I would be really grateful to any one of you who could help me to solve this trouble.

Best regards,

Paul, from France.

[andrewwynn]

New ≠ fixed. Your symptom suggest one or more wheel sensor is not reporting correctly.

Why'd you replace all four if only one affected?

Did you use OEM brand?

Do you have a scanner that will show you real-time wheel speed. See if you can find a speed where one wheel shows different value. Usually the computer will only report whole or half numbers but maybe at 60.0 m mph or xxx rpm you can get three to agree and one is different.

[Paulfromfrance]

Originally Posted by andrewwynn

New ≠ fixed. Your symptom suggest one or more wheel sensor is not reporting correctly.

Why'd you replace all four if only one affected?

Did you use OEM brand?

Do you have a scanner that will show you real-time wheel speed. See if you can find a speed where one wheel shows different value. Usually the computer will only report whole or half numbers but maybe at 60.0 m mph or xxx rpm you can get three to agree and one is different.

Hi andrewwynn,

Thank for your reply.
First I changed only front left abs sensor, and the trouble was there.
Then I changed the three others, with new original BMW parts.
I don't have access to a wheel speed scanner.
Even if one sensor sends a wrong information, it doesn't explain that the computer refuses to reset the system, no?

[wpoll]

Originally Posted by Paulfromfrance

... Even if one sensor sends a wrong information, it doesn't explain that the computer refuses to reset the system, no?

That is the perfect explanation...

[Qsilver7]

Here’ some info about the RPA (flat tire monitoring system) on the e53 X5:

[andrewwynn]

From the description above describe more accurately what's happening. Eg color of indicator b and Bing sound etc. Any written message.

You can't do serious DIY repairs without a scanner. The best for e53 is the foxwell nt510 or nt520. They can be found on eBay very reasonable

[Paulfromfrance]

Thank you very much for these precious informations. I forward them to my mechanical.

[Paulfromfrance]

Originally Posted by andrewwynn

From the description above describe more accurately what's happening. Eg color of indicator b and Bing sound etc. Any written message.

You can't do serious DIY repairs without a scanner. The best for e53 is the foxwell nt510 or nt520. They can be found on eBay very reasonable

My car was scanned with a dedicated software on a computer but I didn't find any reliable information concerning my tyre pressure signal. I have to admit that searching and interpreting some some results was far from obvious. I may buy the fox well device, thanks for this advice.

By the way, I complete my clues list:
Since a long while, my steering wheel vibrates significantly between 60 and 70 mph on left light curves, so on right side support, and nearly not at all on right light curves, so on left support. I suppose then that my front left drive shaft is worn out or damaged.

My additionnal question is :
Do you think that a worn out drive shaft could disturb the wheel turn counting and be the cause of my tyre pressure warning failure?

[andrewwynn]

The symptom you describe of wobble on slight curve is almost always from the front axle rear control arm ball joint.

The two tests to confirm:

1) gentle brake from 50-40 mph
2) at 60-70 mph make very gentle "s curve" on the center lane of a freeway (so you are on the top of the crown)

With #1, you'll get wobble on the steering on initial brake application that will stop once it gets firm.

With #2: you hold the wheel with just thumb and one finger to allow it to wobble; as the wheel passes dead center you'll get 1-3 wiggles fighting the cross.

I had this issue for about two years and even after replacing all control arms and ball joints still once in a while on certain roads I'd get the same exact wiggle!

Infuriating!

Turned out to be steering rack!

With engine off I had a buddy steer back and forth and could feel the clunk as the gear worked through some backlash!

FYI I still have the replacement rack as my car was totaled by a deer just before I got to install it.

[andrewwynn]

No on worn driveshaft but Definitely get a precise measure of the rolling circumference, also what psi are your tires? I always have my tires set to the loaded standard which was ≈ 32/39 (going from memory).

I would try either going to the higher rear psi or if already, go to all the same.