[grundoon]

Looks like Fisker mixed up my rear left with my rear right air pressure readings on the diagnostics.

 

[AlJOHN]

??? don't understand. Could you be more specific.

 

[rmalzo]

the tires probably just got switched around. It happened to me too

 

[JCMorrill]

Why does that matter? (moving tires right and left -- obviously front to back is impossible).

 

[AlJOHN]

Still confused. I rotate the tires right to left every 5K. No affect on the diagnostics that I have noted.

 

[grundoon]

The air pressure of the rear left is the right and vise versa. Ok I should label the rims Rear left and rear right with a jiffy marker next time the tires come off.

 

[AlJOHN]

@grundoon -- Did you have a rear tire fail. If it is normal pressure, I have not seen any tire pressure readings. They only appear when a tire is over- or under-pressure. So are you saying when the tire was "low" it indicated on the wrong side of the car. Again, I didn't think the sensors were location sensitive. Most tire pressure systems communicate to the pickup on the same wheel location. I defer the experts on the Karma on exactly how it works. But in all the cars I have owned, this is not the case since manufacturer's expect the tires to be rotated.

 

[Harleyguy]

The sensor are programmed to the location of the tires . When we program the system the tool has us walk around the car starting from the left wheel ending at the left rear wheel . Each time the VCM sees the sensor the horn honks at the last sensor a double honk meaning the system is programmed .

 

[JCMorrill]

Oh, so the tire pressure communication to the car is "wireless" and computer thinks that the ID of the wheel on the left is really the wheel on the right. Is that "the problem"?

 

[AlJOHN]

Thanks Harleyguy..... Never had occasion to notice (fortunately). On my Audi's, if the tires are changed, the driver just press "set tire pressures" in the "CAR" menu so rotating isn't an issue. I went a checked the menu's because of the thread to see if I missed something. Appreciate the "teach".

 

[Harleyguy]

Oh, so the tire pressure communication to the car is "wireless" and computer thinks that the ID of the wheel on the left is really the wheel on the right. Is that "the problem"?

Correct the sensor have small batteries in them that's suppose to last for years but unfortunately I find them failing early on the Karma. The VCM remembers the id of each sensor and its location .
I will try and post a screen shot of the screen

 

[grundoon]

Computer was wrong

Originally Posted by JCMorrill View Post
Oh, so the tire pressure communication to the car is "wireless" and computer thinks that the ID of the wheel on the left is really the wheel on the right. Is that "the problem"?

Yes that is the problem.

 

[Stefan]

What will happen, if you do it in the wrong order: fl,fr,rl,rr?
Wouldn't this course the described effects?

 

[grundoon]

I bought the car with only 5000km (3106 miles) so I would think no one touched the tires since the factory.

 

[JCMorrill]

I'll be sure to caution folks who work on my car/replace tires to keep them straight. Assuming they're right at all right now? ... I keep my tires well inflated, so I usually can't see the TPMS display seeing as it won't show you unless there's a fault. :s

 

[tbjorge]

Just changed to my summer tyres, and since I did not read this thread first, I did not think the wheels are sensitive to the position on the car. I understand from the above they are, or, more correct, after programming, they become sensitive.

Since the tires did not come with RR / FL / FR / RL marking, any chance of finding this out, or will I have to try the different position ? Luckily front and rear wheels are different, so that limits the alternatives significantly.

Appreciate feedback before starting moving around wheels, guess that the last alternative will be the correct one......

Kr/Tor

 

[Stefan]

No idea, but I would deflate the front right wheel and take a slow ride... It should tell, which tire needs air...

Either just inflate it or inflate and change it to the left.

Do the same on the rear end.

As I said... I don't know better!

 

[tbjorge]

Thanks Stefan, not a bad idea at all - hopefully the low pressure alarm will be given priority over the wrongly located wheel(s)....

 

[Stefan]

I don't think, the sensors 'know' where they are located... I think they just report...
And I also don't think, that they have some kind of gyro sensors, which might make them wonder, why you are driving reverse, all day

 

[JCMorrill]

The sensors are initially programmed and then believe from then on that they are at a specific corner of the car. Now, since our wheels are different front to back, you have a 50/50 chance with each pair of tires to randomly put them back on correctly. But, neither the car nor the sensors know if they've been swapped and the TMPS will display incorrectly if they have.