So I found a guy online who has factory Toyota TPMS sensors in individually boxed red and white boxes with the number label and all that sub valve assembly tire / whatever I'll put the part number up here if I have to but you can find the guy on eBay You can't miss the pictures of the boxes I ordered a set of four I think that's how we sells them they're like $44. In the immediate thing I noticed directly on the sensors themselves if you have the valve aimed down holding the unit in your hand on the left side of the unit on the Toyota Pacific branded TPMS sensors there's this thing called the CMIT number printed right on the very edge of the sensor all the fakes are what we're calling fakes or seconds And what have you that I've purchased do not have that CMIT number scribed on the edge of the black plastic in white. So it seems that's a way to tell the real ones from Toyota from the seconds or whatever these other ones are I don't doubt these other ones are made by Pacific manufacturing they're just not made by Pacific to be reboxed in Toyota boxes for Toyota to sell. All of them so far that I've bought work just fine they're in use right now and the lights are off on the dash and everything seems good so.
There isn't people here always screaming about fakes and you know they won't work or they something and something I don't know personally My fakes are working fine. They look like their seconds from the manufacturer Pacific is all that is and the real ones as far as I can tell from the Toyota and Toyota packaging have this CMIT ID along the side of the sensor every one of them The seconds or the fakes or the ones that I'm talking about do not have the CMIT number but I don't care about a number I care about the TPMS light being off I also have a Toyota Prius with a set of ACDelco TPMS sensors in it and they work fine apparently as long as they broadcast on the same megahertz gigahertz range You're in pretty good shape I guess
The batteries and what look to be the true units from the in the Toyota boxes have Panasonic batteries in them I have to go look and see what we think the seconds or the copies of the Pacific branded sensors have in them The panasonics and the factories are Chinese batteries it says so right on the battery I just can't remember what we're in what I think or seconds or fakes that don't have this CMIT number on the side of the casting
There are probably high-quality fakes that are not much different from the original when installed and perform their functions well. In this case, it is difficult to call it a fake. Rather, it is a good-quality duplicate.
The sensors usually have a 3V lithium battery. It lasts for several years. I have seen universal sensors where the battery can be easily replaced. But the wheel needs to be dismounted to get to the sensor.
I don't think CMIT # is the indicator for genuine. In fact, it is likely the counterfeit from my sample data. The original TPMS sensor came out of my 2011 Prius has no CMIT #. No Toyota Markings. They are made by Pacific Industries. Denso 550-0103 is exact match (~$40 sold by amazon/rockauto). Also no CMIT # and made by Pacific Industries. Denso is just the distributor. Bought 4 from amazon for $40+ each and been on the car for 2.5 years without problems. Also checked the ID codes are properly registered in Techstream. Original electronics is entombed in white silicone while new Denso is clear silicone. Here is pic of original and the Denso/Pacific Industry replacement Also looking into replacing battery on my original 2011 TPMS to help a college student's 2008 Lexus RX350 with TPMS light (New TPMS incl spare is $$$ for college student) OEM battery legs are soldered in from the bottom of the TPMS board. Appears same from the amazon reference picture for Denso replacement ( link ) which also seems to have eliminated the rear plastic cover. OEM TPMS battery is Panasonic Japan BR2450A. Closest matching electrode tab version on mouser/digikey is BR2450A/FJN ( link ) Drawing shows a date code which was on my OEM TPMS's battery. On 4-5x TPMS on ebayfor <= $50 (all stamped Pacific Industries and has CMIT #), there are some key differences from the Denso for ~$40+ (Amazon, rockauto) Cheap ebay TPMS's circuit board patterns are different than the Densos through the transparent silicone. Some picture even shows no silicone moisture protection but maybe just reference pics. Cheap ebay TPMS's battery is China Panasonic/Maxell etc CR2540 Not saying cheap ebays aren't as good but they are likely counterfeit. Chinese manufacturing has evolved to provide many grades from the lowest to the highest (I repair iPhones and source my parts including the battery from distributors supplying professional repair shop. Grades are much higher than ebay/amazon junk @ same price) I actually did some manufacturing in China saw the quality drop off as you go from coastal factories to inland factories (cheaper, lower quality) So the real difficulty is to know which grade manufacturer made the product.
Opened up a common no name brand TPMS from China. This one didn't copy Pacific Industries perfectly but in the general shape. Internal components are quite revealing. Its likely the internal component source is how majority of the cheap no name brand TPMS are made. I have a bit of chip design and chip fabrication background so who did the design and fabrication tells quite a bit. External TPMS looks quite similar to this one on Amazon and has the same company logo The Chip The chip is a AutoChips AC5111DBN. I know AutoChips well, they are one of the Chinese main chip design company for the cheap Android head unit available today. I have one in my Prius haha. For the headunit, these are Android Applications Processors. Think of it like the main chip in an Android phone but much less requirement for tiny size and low power operation. AutoChips by their name indicates targeting chips for cars. Here is a bit of history on them AutoChips Inc.（company）_Baiduwiki Founded in 2013, designed China's first integrated TPMS chip AC5111 in 2019. So I'd imagine all the $10/TPMS sensors appeared right after this time frame as cheap chip source became available. Here is the chip and its internal gory detail if anyone is interested. AC5111DBN/F2C | AutoChips | Pressure Sensors | JLCPCB TPMS chip require a fairly unique chip fabrication capability. There is analog sections and digital sections on the chip. This is called mixed signal chip and requires specialized expertise. Furthermore, it includes MEMS chip sections for the accelerometer and pressure sensor. MEMS stands for Micro-Electro-Mechanical Systems. Imagine a little tiny microscopic beam (like a wood beam in your house) that has tiny mass. When the chip is accelerated, the beam flex and amount of deflection is measured as acceleration rate. Was first mass produced way back in the late 80s by US company and quickly became key component for firing airbags. Anyway mix analog, digital, and MEMS all on one chip requires 10-20 years of expertise beyond just making regular chips. I was wondering if China's domestic chip fabrication have reached this level. The answer is no. Autochip's TPMS chip is fabricated at X-FAB, a German company/factory with roots in East Germany chip factory before the Berlin wall. AutoChips and X-FAB Launch Mass Production of China’s First TPMS Chipset: X-FAB X-Fab - Wikipedia Anyway, they are the source of expertise and factory for mix signal + MEMS on one chip. The Battery Labeled maxell CR2450HR. I could only find this image in a KIA TPMS tear down that might be a reliably authentic source. All other images I found were little sellers on ebay/walmart/aliexpress etc. TPMS battery replacement - Maxell CR2450HR EX battery - Page 1 The character labels markings seems to be more finely etched on than what I found in TPMS tear down above. I wouldn't imagine this is genuine Maxell but just a guess of course. Here is Maxell's main Asia subsidiary's website in Hong Kong and the consumer battery section Energy Products – Maxell Again, the etching print seems finer then the one I extracted. Don't know if thats just the consequence of aiming at end consumers instead of bulk supply to factories. Generally speaking, all the factory bulk supplied components I've seen are basically identical visual quality to their lower volume sold to consumer cousins. ==== So what does this mean? Its quite likely just like AutoChip's low cost Android headunit product, they have to provide the functions but aggressively cut cost. I've no idea where the TPMS chips cut some corners but given the toughest design constraint is low power for TPMS, maybe some corners cut here... I don't know. Its just a guess. I do know where they cut all the corners on the Android head unit chip ( I actually run a website to help people flash the firmware on these head units ( link if you are curious, maybe you have one haha ) The chip tick all the check boxes.. But by the time these chips got into small low end headunit sellers, 4 core became 8, Android 9 became 13 etc. The head unit chip runs quite slow compared to other headunit chips. Anyway, its understandable. My Prius 10" head unit was $100 with a backup camera + all wiring harness + Prius fitting plate. I was also wondering if Chinese TPMS chips were made in Chinese chip factories and this answers the question (no) China's chip fabrication is much younger than US+Taiwan+Korea+Japan and main focus is catching up on computer and phone chips rather than very specialized mix signal + MEMS chip fabrication knowledge. So make sense to keep domestic capabilities focused on catching up to the west on the main chip fabrication than to spend capabilities focusing on a specialized fabrication. X-FABs looks to be amongst the top MEMS chip fabrication (called foundaries) in the world. Anyway, good to know whats inside one of these $10 TPMS sensors. Don't know the benchmark differences between Autochips and what is found in say Pacific Industries (have their own chip fabrication facility in Japan) If design remains static, then parity would be easier.
Thanks for sharing your dive into these sensors. I, for one, certainly appreciate your efforts. I hope it encourages other similarly talented members to dive in and share their experiences with different components and tech.
