06-30-2015, 09:20 AM | #1 |
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Quest to disable TPMS (and activate FTM) COMPLETED
EDIT: MISSION COMPLETED
LATER EDIT: Here's the TL/DR explanation of what I describe below. For various reasons, I wanted to have tire pressure monitoring without having to deal with those pesky sensors. And now, after some tweaking and coding, that's exactly what I have. I can swap summer and winter wheel/tire sets - neither of which has TPMS sensors - whenever I want, and my car will still alert me if one of them has low pressure. BACKGROUND INFO: US Spec E84 models (and maybe some more recent specs for other countries) use the TPMS system that relies on individual pressure monitors in each tire. If you have metal valve stems, you have this type of TPMS. Up until very recently, most other countries use a system called FTM that relies instead on monitoring the tires via the ABS sensors. FTM basically looks to see if one tire is rotating at a higher speed than its opposite-side partner, which indicates that it has a lower level of inflation. FTM works pretty darn well, but US regulations require TPMS in newer cars. So for some cars, like the E84, BMW just added in the TPMS system in addition to the existing FTM system. Since FTM is tied to the ABS monitors, I guess it really didn't make any sense to change the production and remove it for TPMS markets. The upshot of this is that US-spec E84's have a sensor-based TPMS system because it's the law, AND they have a fully working sensor-less (sort of) FTM system because BMW didn't bother removing it. So my quest was to disable the TPMS system and enable FTM, which will make things much easier and less expensive when it comes to swapping wheel sets and replacing tires. Disabling TPMS would have been enough, honestly. I managed to survive the past few decades with manually checking my tire pressure. But I wanted to go the extra mile and retain the additional level of safety provided by automatic tire monitoring. Here are the results: After getting some help from a couple of very nice European folks I was able to figure out the coding. Full details: ***PLEASE NOTE I AM NOT RESPONSIBLE FOR ANY DAMAGE YOU DO TO YOUR VEHICLE IF YOU DECIDE TO TRY REPEATING ANY OF THIS**** 1) Disable/disconnect physical TPMS RDC module. The specifics are further down in this thread, but basically it should be under the car and behind the rear axle. 2) Code OUT $2VB and ADD IN $265 in the VO. 3) Change the following codes in CIC, KOMBI, and XDSC: CIC: RPA_CIC aktiv CIC: RDC nicht_aktiv CIC: RDC_SAFETY nicht_aktiv KOMBI: RDC_ALIVE nicht_aktiv KOMBI: MMI_ENA_RPA_RDC aktiv KOMBI: RDC_VERBAUT nicht_aktiv KOMBI: DSC_MIT_RPA_CC aktiv KOMBI: RDC_DISP_SWITCH nicht_aktiv XDSC: AUSSTATTUNG_RPA aktiv And that was it. Then you can go into the status menu. If you go to the Flat Tire Monitoring System tab, it should see there is an error. Just go to the 2nd tab and reset it. Then you should see green in all corners. RPA FTM is now working on my US-spec E84. But does it really work? As a test I dropped the right rear tire down from 41 to about 29 psi. I then drove for less than a mile and got this: VERDICT: COMPLETE SUCCESS Thanks so much to everyone who helped me out with this! Last edited by improvius; 08-13-2015 at 10:45 AM.. |
06-30-2015, 05:55 PM | #3 |
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I'm 99% sure it has to be physically disconnected before you can code it out. I've been going over the whole process and everything I've found indicates disconnection is required: http://www.e90post.com/forums/showthread.php?t=728429
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07-01-2015, 09:37 AM | #4 |
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Yeah I saw those, but they are pretty old and pretty inconclusive.
Call this shop: http://www.bpmsport.com/services/cod...motion-58.html or http://www.alpinemss.com/product_p/rme.htm |
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07-05-2015, 10:08 AM | #10 |
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Well, I got the panel off (after removing the hatch sill as I expected, but the RDC is nowhere to be found. It seems unlikely, but I guess I'll try the driver's side panel next, even though I don't see any wiring going directly over there. If I don't find it there, I'll probably just give up and go to the local dealer.
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07-07-2015, 02:47 PM | #15 |
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Just found this note.... I looked under my car and there it is. Its a combo aerial and RDC module.
Tyre Pressure Monitor (RDC) The Tyre Pressure Monitor (RDC) is a system which monitors the tyre pressure while the vehicle is in motion. It is offered exclusively in the USA (legal requirement) and as optional equipment (SA2VB). The system of the new generation (Generation 3) now consists only of 5 components: the RDC control unit (control unit with integrated reception aerial) and 4 sets of wheel electronics. RDC control unit Assignment of wheels Axle assignment and identification of direction of rotation can help to assign the Identification Feature (ID) of the wheel electronics to a defined installation position. Axle assignment: The RDC control unit is installed close to the rear axle. For this, the messages on the wheel electronics from front axle and rear axle differ to varying extents. The averaged signal strengths of the wheel electronics systems thus indicate the axle assignment. Since the RDC control unit is installed to the rear of the vehicle, the wheel electronics on the rear axle receive signals at a higher level of receiving power than those on the front axle. Axle assignment runs parallel in time to the idenfication of direction of rotation. In the calculation of signal strengths, only wheels rotating in the same direction (on each side of the vehicle) are taken into account. Last edited by X1Denver; 07-08-2015 at 10:36 AM.. |
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07-07-2015, 03:02 PM | #17 |
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YEP the EKPS or Fuel pump module is where you were. I hope this helps. You should change the thread to "delete TPMS" when you figure it all out. I hope so as I don't care for TPMS, especially with my cold winters.
Last edited by X1Denver; 07-07-2015 at 03:12 PM.. |
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07-07-2015, 05:45 PM | #19 |
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Okay, found it, unplugged it, and recoded to disable it. I think it's good, will try test driving in a bit. I had to pull down a piece of the plastic shielding in order to disconnect the module. There are just a couple of 10mm bolts you need to take out, and you'll have enough room to work with. The passenger side of the TPMS "holster" or whatever you want to call it flips down (once you've removed the shielding and made some room), and from there you can just pinch the connecting harness and pull it off of the module. I just wrapped the harness up with some electrical tape and shoved it back under the shielding.
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07-07-2015, 06:07 PM | #20 |
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In the above you can see the TPMS module disconnected. The shielding is loosened and the holster is flipped open toward the camera The harness is hanging completely disconnected from the module in the background. I had a quick drive around the block with no warning lights or errors. Next step is to see if I can enable the ABS-based tire monitoring. |
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07-07-2015, 06:15 PM | #21 | |
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Quote:
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