Tire Pressure Readings (RDC) Vanished

Delray

Active member
Had a minor issue with tire pressure readings.

Posting this in case someone has a similar issue and is searching for info ....

Two days ago, my dashboard tire pressure readings disappeared (well-kept 2013 BMW C650 GT with 18,800 miles).

I knew it wasn't simultaneous failure because I replaced the rear sensor four months ago and the front sensor is OEM (8 years old).

For two days, nothing. All I saw was two dashes for each tire ... "- - " and "- -".

I figured the problem must be electrical or computer-related. I began my journey into the BMW Matrix by checking the fuse. My 2015 Owner's Manual shows a 4 amp fuse for the tire pressure circuit, although my 2013 has a 7.5 amp fuse in that socket. The fuse was fine. Just to try SOMETHING different, I switched the tire pressure fuse with an adjacent 7.5 amp fuse and made sure it was sitting tightly when I replaced it.

Voila. Problem solved. It's been fine for the last two days. Loose fuse? Inexplicable glitch or coincidence? Don't know. My next move would have been to plug my OBDLink into the bike and use Hex Code diagnostics. Glad I didn't need it.

Only conclusion I can draw: if your tire pressure readings vaporize, first, make sure your fuse is good and sitting tightly. It's shown in the owner's manual, #3, third from the right on the top row; fuses are behind the upper right fairing.

Also worth noting: My tire pressure readings have been reliably 3 lbs. lower-than-actual. When I see the readings, I automatically add 3 lbs. per tire in my head to get an accurate number. Not a perfect system, but I love the feature. I use it every time I start riding to make sure there's proper air in the tires.
 
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slant911

Active member
Good catch. Always start with the easiest stuff. I have noticed also that the pressure readings consistently read about 3 psi low of reality.
 

Rooltje

New member
Had a minor issue with tire pressure readings.

Posting this in case someone has a similar issue and is searching for info ....

Two days ago, my dashboard tire pressure readings disappeared (well-kept 2013 BMW C650 GT with 18,800 miles).

I knew it wasn't simultaneous failure because I replaced the rear sensor four months ago and the front sensor is OEM (8 years old).

For two days, nothing. All I saw was two dashes for each tire ... "- - " and "- -".

I figured the problem must be electrical or computer-related. I began my journey into the BMW Matrix by checking the fuse. My 2015 Owner's Manual shows a 4 amp fuse for the tire pressure circuit, although my 2013 has a 7.5 amp fuse in that socket. The fuse was fine. Just to try SOMETHING different, I switched the tire pressure fuse with an adjacent 7.5 amp fuse and made sure it was sitting tightly when I replaced it.

Voila. Problem solved. It's been fine for the last two days. Loose fuse? Inexplicable glitch or coincidence? Don't know. My next move would have been to plug my OBDLink into the bike and use Hex Code diagnostics. Glad I didn't need it.

Only conclusion I can draw: if your tire pressure readings vaporize, first, make sure your fuse is good and sitting tightly. It's shown in the owner's manual, #3, third from the right on the top row; fuses are behind the upper right fairing.

Also worth noting: My tire pressure readings have been reliably 3 lbs. lower-than-actual. When I see the readings, I automatically add 3 lbs. per tire in my head to get an accurate number. Not a perfect system, but I love the feature. I use it every time I start riding to make sure there's proper air in the tires.
 

Rooltje

New member
The same happened to me. When I asked the BMW dealer where I purchased my scoot, they told me that the control unit needed replacing for AU$750. Obviously, I did not go ahead. At home, I researched the problem myself, I discovered it was just an issue with the fuse.
 

Anouar ny

New member
Had a minor issue with tire pressure readings.

Posting this in case someone has a similar issue and is searching for info ....

Two days ago, my dashboard tire pressure readings disappeared (well-kept 2013 BMW C650 GT with 18,800 miles).

I knew it wasn't simultaneous failure because I replaced the rear sensor four months ago and the front sensor is OEM (8 years old).

For two days, nothing. All I saw was two dashes for each tire ... "- - " and "- -".

I figured the problem must be electrical or computer-related. I began my journey into the BMW Matrix by checking the fuse. My 2015 Owner's Manual shows a 4 amp fuse for the tire pressure circuit, although my 2013 has a 7.5 amp fuse in that socket. The fuse was fine. Just to try SOMETHING different, I switched the tire pressure fuse with an adjacent 7.5 amp fuse and made sure it was sitting tightly when I replaced it.

Voila. Problem solved. It's been fine for the last two days. Loose fuse? Inexplicable glitch or coincidence? Don't know. My next move would have been to plug my OBDLink into the bike and use Hex Code diagnostics. Glad I didn't need it.

Only conclusion I can draw: if your tire pressure readings vaporize, first, make sure your fuse is good and sitting tightly. It's shown in the owner's manual, #3, third from the right on the top row; fuses are behind the upper right fairing.

Also worth noting: My tire pressure readings have been reliably 3 lbs. lower-than-actual. When I see the readings, I automatically add 3 lbs. per tire in my head to get an accurate number. Not a perfect system, but I love the feature. I use it every time I start riding to make sure there's proper air in the tires.
Thank you for the lead, I’ll check that this weekend
 
The same happened to me. When I asked the BMW dealer where I purchased my scoot, they told me that the control unit needed replacing for AU$750. Obviously, I did not go ahead. At home, I researched the problem myself, I discovered it was just an issue with the fuse.
The BMW Dealers want to sell you something that you do not need. They are out to make $$$$
 
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DrCohen

Member
Had a minor issue with tire pressure readings.

Posting this in case someone has a similar issue and is searching for info ....

Two days ago, my dashboard tire pressure readings disappeared (well-kept 2013 BMW C650 GT with 18,800 miles).

I knew it wasn't simultaneous failure because I replaced the rear sensor four months ago and the front sensor is OEM (8 years old).

For two days, nothing. All I saw was two dashes for each tire ... "- - " and "- -".

I figured the problem must be electrical or computer-related. I began my journey into the BMW Matrix by checking the fuse. My 2015 Owner's Manual shows a 4 amp fuse for the tire pressure circuit, although my 2013 has a 7.5 amp fuse in that socket. The fuse was fine. Just to try SOMETHING different, I switched the tire pressure fuse with an adjacent 7.5 amp fuse and made sure it was sitting tightly when I replaced it.

Voila. Problem solved. It's been fine for the last two days. Loose fuse? Inexplicable glitch or coincidence? Don't know. My next move would have been to plug my OBDLink into the bike and use Hex Code diagnostics. Glad I didn't need it.

Only conclusion I can draw: if your tire pressure readings vaporize, first, make sure your fuse is good and sitting tightly. It's shown in the owner's manual, #3, third from the right on the top row; fuses are behind the upper right fairing.

Also worth noting: My tire pressure readings have been reliably 3 lbs. lower-than-actual. When I see the readings, I automatically add 3 lbs. per tire in my head to get an accurate number. Not a perfect system, but I love the feature. I use it every time I start riding to make sure there's proper air in the tires.
The owner's manual says "The displayed tire inflation pressures refer to a tire air temperature of 68 °F (20 °C)." Perhaps this is the reason for the 3 lb discrepancy?
 

Delray

Active member
"The owner's manual says "The displayed tire inflation pressures refer to a tire air temperature of 68 °F (20 °C)." Perhaps this is the reason for the 3 lb discrepancy?"

Interesting theory. In South Florida, we only have a few months where the temperature gets down to 68 degrees each day.
 

DrCohen

Member
"The owner's manual says "The displayed tire inflation pressures refer to a tire air temperature of 68 °F (20 °C)." Perhaps this is the reason for the 3 lb discrepancy?"

Interesting theory. In South Florida, we only have a few months where the temperature gets down to 68 degrees each day.
If you fill your tire when it is 98degF, it will be about 3 lb lower at 68degF.
 

Delray

Active member
"If you fill your tire when it is 98degF, it will be about 3 lb lower at 68degF."

I'm convinced it's the RDC system. It reads 3 lbs. less for each tire in heat or cold. I have three (3) tire gauges I know are accurate from several years of use. Twice, I've returned from a dealer after having new tires put on the rims of this bike and set to a precise psi's, then checked the psi's against my three gauges. They agreed with the dealer psi both times, but sure enough, the bike reported 3 psi lower both times.

Luckily, the bike readings are very consistent (albeit three lbs. off). I simply do the "RDC + 3" math in my head. Honestly, I'm less concerned about being a pound or two off; I'm no performance rider. I just like to verify that I don't have a flat before each ride.
 
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moodleman

New member
Interesting thread. I have only had my C650GT for 3 months. It is a 2018 model. The only display of tyre pressure since I have owned it is "--" and "--". I have reached the conclusion that my model is not fitted with TPMS - but perhaps it is and the system is malfunctioning! Will check those fuses tomorrow!
 

Delray

Active member
"Will check those fuses tomorrow!"

If the fuses are fine, the next place I'd look is inside the tires. The sensors are frightfully expensive, around $200 USD + installation, although here is a link to a cheap, Chinese knock-off for one-tenth the price. To avoid dealer installation costs, I took the rear tire off the bike and drove it to a little motorcycle shop to remove the rubber and replace the sensor -- one T-30 torx bolt holds it in place. Since last May it's been working well over 3,000 miles. TPMS (RDC) is a big plus of this bike and worth the effort to make it work.

https://www.ebay.com/itm/124590127787?hash=item1d02267aab:g:OW0AAOSw-npgNR~F

Also possible that you have the sensors and no one ever "woke them up." That takes a cheap, simple tool ....


Here is a thread about the TPMS sensor I installed ....

 
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