Hi, I have a US purchased 2007 GL-450 up here in Canada now.

The TPMS system worked fine and showed individual tire pressures (in bar, not psi) when I drove it home.

The dealer here in Saskatoon had to put a metric speedometer head on it to allow import to Canada and obviously changed the firmware because the odometer now reads kilometers instead of miles. That’s all fine, except the individual wheel pressure display went away and now only a statement about “tire monitoring system active” is present. There is also a “run flat system active” message that I understand is based on ABS sensed tire rotational speed – that seems to be fine, but the TPMS presentation has changed. That is problem #1.

Did the dealer not put the right software in it, or did he not turn something on? I have read there are multiple TPMS systems out there with various capabilities. My wife’s Canadian bought 2008 CDI GL350 has only the run flat system installed for example.

But wait, it gets worse….problem #2

For summer use, I put a set of Avarus 22” wheels bought at TireRack on her. I did get the TPMS sensors installed to the new wheels at TireRack. The wheels are a bit larger than I would go for again and perhaps a bit too “pimped”, but the chrome wheels on the black paint look sharp.

When I put the new wheels on, I got a “tire monitoring system inoperative” message. All tire pressures are correct and the dealer does not seem to know how to make it work. The dealer said I might have to drive it for a few days. Of course a few days have gone by and it still does not work – shocking I know.

TireRack says the dealer has to “marry” the car to the new sensors and that I will have to re-marry every time I do a seasonal wheel change. True story?

Another Benz dealer in a nearby city says I should have to do nothing… the new sensors should be read just like the old ones. Any knowledge out there on this?

Does the TPMS system in the car need to be told about new sensors (new wheels)? The “reset” function available on the steering wheel / dash display does nothing for the problem.

But wait, it gets even worse…..problem #3

In an effort to convince the dealer the system should work, I rolled the loose factory rims with the winter tires on it up against the summer wheels and turned the power on. The system “saw” the factory rims and while it didn’t report individual pressures (see problem #1 above), it did report that it was operational. Thus proving there is no need to drive for a few days, and proving the system “likes” the factory sensors.

Thinking I would check out the TireRack sensors I had a tire shop swap the TPMS sensors from the factory rims into the new big rollers. The ones in the TireRack rims do look correct and very similar to the factory units, Both are Siemans VDO 433 Mhz. But NOW, even the factory sensors in the new rims don’t work.

I have double checked the tire pressure, “reset” the dash a few times and no luck. The only thing I can think of is that either the tire shop damaged a sensor, or that they mixed up the position of the sensors on the car (ie LF is now on RR or some new combination). Is the system married to a particular sensor being on a particular wheel position?…. as in each sensor is coded with a unique ID? That would seem like a needless hassle and would definitely mean a visit to the dealer’s computer every time a tire set was changed or rotated.

Help please!!!! Thanks in advance for any insight on my dilemma.

 

from what you have written a re-initialization should fix the problem .... perform the re-learn procedure (only once) with only 1 set ofthe tires/wheels in close proximatey to the vehicle and 'all' of the issues should go away. It sometimes takes several miles for everythingh to sync up ... your ABS wheel speed sensors are do not participate in the TPM system on your vehicle