TPMS says one tire has 0 psi; gauge reads 40 psi
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MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,124
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From: Milton/Westport, MA USA
me: 2015 SL400 & 2015 ML400; wife: 2022 GLC Coupe; daughter: 2017 GLC SUV
TPMS says one tire has 0 psi; gauge reads 40 psi
So my wife hasn't driven her C300 at all for a few weeks, what with the clampdown and all, but she ventured out the other day for a quick errand. A few hours later, we decided to use her car for a weekend trip, and when I started it the TPMS warning was on. She said she had seen it earlier, and it was only off a pound or two. You know it won't read values until you drive for a few minutes so I grabbed my compressor just in case and set off. At the end of our street the alert turned red and it showed 0 psi in the right front, 40 psi everywhere else. She has 17" wheels so not low-profile at all, and tire looked fine, but I fired up the compressor anyway and as soon as I connected it the analog gauge showed 40 psi. I'm assuming a bad sensor but I've had many TPMS issues on other models and I've never had one read 0 psi, though I have had older models where it just said "no connection" or something similar. Car has about 65,000 miles and the front tires were replaced about a year ago (FYI, I swear the rears are original!)
Senior Member
Joined: Jul 2019
Posts: 286
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From: Bay Area, CA
2016 C300W4 (W205), Luxury Pkg, Diamond Silver Met. and Silk Beige\Espresso Interior
The TPMS sensors in the wheels are battery operated. They have CR2032 lithium batteries that have a lifetime of about 5-6 years before they need to be replaced.
The batteries are integrated (soldered) into the unit, so they are usually replaced outright with a new unit in the wheel and programmed into the system by the installer.
The batteries are integrated (soldered) into the unit, so they are usually replaced outright with a new unit in the wheel and programmed into the system by the installer.
Thread Starter
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,124
Likes: 222
From: Milton/Westport, MA USA
me: 2015 SL400 & 2015 ML400; wife: 2022 GLC Coupe; daughter: 2017 GLC SUV
The TPMS sensors in the wheels are battery operated. They have CR2032 lithium batteries that have a lifetime of about 5-6 years before they need to be replaced.
The batteries are integrated (soldered) into the unit, so they are usually replaced outright with a new unit in the wheel and programmed into the system by the installer.
The batteries are integrated (soldered) into the unit, so they are usually replaced outright with a new unit in the wheel and programmed into the system by the installer.
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Joined: Nov 2003
Posts: 2,413
Likes: 497
From: Earth
2015 C300 4Matic Sport
So my wife hasn't driven her C300 at all for a few weeks, what with the clampdown and all, but she ventured out the other day for a quick errand. A few hours later, we decided to use her car for a weekend trip, and when I started it the TPMS warning was on. She said she had seen it earlier, and it was only off a pound or two. You know it won't read values until you drive for a few minutes so I grabbed my compressor just in case and set off. At the end of our street the alert turned red and it showed 0 psi in the right front, 40 psi everywhere else. She has 17" wheels so not low-profile at all, and tire looked fine, but I fired up the compressor anyway and as soon as I connected it the analog gauge showed 40 psi. I'm assuming a bad sensor but I've had many TPMS issues on other models and I've never had one read 0 psi, though I have had older models where it just said "no connection" or something similar. Car has about 65,000 miles and the front tires were replaced about a year ago (FYI, I swear the rears are original!)
Try driving the vehicle for a while until the PSI values show again (on the three tires), then press the down arrow and set the reference values. TPMS will restart/reboot. (See if that fixes it)
If that works, reset the reference values again to proper PSI numbers.
Thread Starter
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,124
Likes: 222
From: Milton/Westport, MA USA
me: 2015 SL400 & 2015 ML400; wife: 2022 GLC Coupe; daughter: 2017 GLC SUV
It was a bad sensor, which they replaced, $124.48 for the part, $161.81 for labor, $21.48 "miscellaneous charges", total after tax $316.89 I've paid $80-$100 many times at a neighborhood tire shop (generic sensors) so I figure this is just about right for the MB OEM exchange rate. Oh, he waived the diagnostic charge!
