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Discussion Starter · #1 · (Edited)
I have a 2008 Exige 240S that continuously flashes "TPMS fault". I have checked and reset cold tire pressures to spec but the symptom never leaves...
Recently I had the dealer flash the firmware with the newest release and that seemed to help for about 10-12 minutes then - dang! - right back to the same symptom as before. I asked the dealer to contact Lotus for help... dealer was told to replace three out of the 4 tire sensors... after that they will consider sending a more expensive solution. I'm concerned that this will only be a hoop jump and I'll waste my time and get my rims beat up in the process... Has anyone else had this problem? It smells like a system problem to me - seems unlikely that 3 out of 4 would be defective. Bad batch of sensors (build date 11/07) or someone forgot the sensor batteries before installing?
 

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Firstly, welcome to the Lotus Family!

Personally, if the dealer was told by Lotus USA to do something, I'd allow them to attempt repairs to meet the warranty. In this situation, I'd ask they replace all the sensors unless they can show good reason to only replace 3 (which doesn't make much sense unless they know something they are not telling you.).
Look at it this way, if they beat up your wheels, at least it's the dealer who can make it right instead of a tire shop somewhere in bfe. :D
 

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+1

Let the dealer replace the sensors under warranty until they get it right. The situation is not going to cure itself on its own and you don't want to be dealing with this problem when the car is out of warranty. Each sensor contains a pressure sensitive radio transmitter and it is quite possible one or more were damaged during installation or have just plain died.

BTW: The batteries in the sensors are permanently installed during the manufacturing process and are not replaceable. Supposedly the sensors turn off when they are no longer in motion and the batteries are supposed to last 10 years. I have a feeling there will be plenty of cars running around with their TPMS lights permanently on in a few years........
 

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BTW: The batteries in the sensors are permanently installed during the manufacturing process and are not replaceable. Supposedly the sensors turn off when they are no longer in motion and the batteries are supposed to last 10 years. I have a feeling there will be plenty of cars running around with their TPMS lights permanently on in a few years........

Is this how other low tire pressure sensors work with batteries like that? Why wouldn't they make it so the batteries could be replaced? So I guess when they die - you will have to buy a whole new sensor? I wonder what they cost vs the battery. Anyway, last question, is there a way to tell specifically what wheels sensor/battery could be a problem or would you have to replace all of them when something like this arises to ensure all is good (kinda like changing smoke detector batteries)?
 

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Discussion Starter · #5 ·
Thanks, all. I will most likely proceed with the dealer replacing three sensors unless I get a solid lead in another direction. I did ask the dealer "Why three and not four?" The service rep (not a trained mechanic) mentioned that three had shown up on a diagnostics report.

Vishus_1: I don't think the cost is astronomical, my impression was that the batts were replaceable (although tesprit may be correct) and the sensors are recognized individually by the receiver - when low pressure is detected it should display LF, RF, LR or RR in addition to "fault". The manual states that if "TPMS fault" is displayed then there is some sort of general issue with the system.

My nose for troubleshooting keeps telling me that this is a receiver problem - that is why I'm fishing for knowledge here. I could be wrong but - obviously - the jury is still out. The dealer has not yet won my complete trust and confidence as I have had a few other minor issues that seemed to catch them sleepy... such as - Me: "Gee, my erratic instrument cluster behavior seems to be a firmware issue - have you heard about this?" Them: "Oh... wait a minute...I think maybe there is a firmware revision available".

Lastly I would like to add how much I like this vehicle. I'm not a show-off, street racer or car snoot - I just really enjoy great design and handling and the Exige is a dream to drive. I could care less if there's no rear view mirror or easy entry/exit just so long as the SC'd motor keeps making that wonderful sound while I click through the gears on those twisting mountain roads... My biggest problem is shooing away the 15 year old boys with their cell phone cameras every time I park at the local grocery store.
 

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Is this how other low tire pressure sensors work with batteries like that? Why wouldn't they make it so the batteries could be replaced? So I guess when they die - you will have to buy a whole new sensor? I wonder what they cost vs the battery. Anyway, last question, is there a way to tell specifically what wheels sensor/battery could be a problem or would you have to replace all of them when something like this arises to ensure all is good (kinda like changing smoke detector batteries)?
My experience with these sensors has been with the Siemens/Schrader sensors that are a rigid aluminum valve stem and a resin filled plastic transmitter assembly. These are probably the most common sensors on European and Japanese cars right now. The type of sensor that is held to the rim with a strap (a lot of Ford products) may have replaceable batteries, but the valve stem/transmitter style do not. The batteries and electronics are permanently encased in the transmitter housing by filling the housing with resin at the time of manufacture so the only way to replace the batteries is to buy new transmitters. The transmitters retail for about $120 each from most car dealers so they aren't exactly cheap.

As far as being able to tell if you have a broken transmitter or a dead battery, there is testing equipment available that will search for the RF signal from a sensor and will tell you if the sensor has failed. This testing equipment is not cheap at this time either and it is not common for a shop to have it. For now it is usually just cheaper to replace the sensors whether good or bad instead of buying the test equipment.
 

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My experience with these sensors has been with the Siemens/Schrader sensors that are a rigid aluminum valve stem and a resin filled plastic transmitter assembly. These are probably the most common sensors on European and Japanese cars right now. The type of sensor that is held to the rim with a strap (a lot of Ford products) may have replaceable batteries, but the valve stem/transmitter style do not. The batteries and electronics are permanently encased in the transmitter housing by filling the housing with resin at the time of manufacture so the only way to replace the batteries is to buy new transmitters. The transmitters retail for about $120 each from most car dealers so they aren't exactly cheap.

As far as being able to tell if you have a broken transmitter or a dead battery, there is testing equipment available that will search for the RF signal from a sensor and will tell you if the sensor has failed. This testing equipment is not cheap at this time either and it is not common for a shop to have it. For now it is usually just cheaper to replace the sensors whether good or bad instead of buying the test equipment.
Wow - that stinks. :sad: Why are they being made this way so the battery can be replaced if needed?
 

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TPMS fault

The Service guy at Park Place has been to factory training and Lotus told them to replace 3 sensors and not 4 because 1 of the sensors is reading which means the receiver is ok. If you have any questions please feel free to call me at 770-324-6673 - Dave @ Lotus Cars
 

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Discussion Starter · #9 ·
That's actually great info, Dave. Thank you! I think most of my apprehension stems (no pun intended) from my inherent (and healthy) distrust of the auto industry in general as well as a lack of familiarity with the local dealer's service staff. Maybe once we all get to know each other...

My Exige did make my eyebrows wiggle around a bit when it came with the TPMS problem, the weird instrument cluster symptoms, failed roof seals, occasional stalling during idle and a battery that needs charging after it sits for a few days.... Add to that a bit of mushy communication from the go-betweens and "Viola!" I became a nervous nellie. Perhaps we've turned a corner...

This forum is great - glad I googled "Lotus Car forum". Now if only the snow, ice, rain, massive puddles and piles of gravel would disappear so I could get back to the business of driving the little beast.
 

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I feel your pain...my s240 has had some issues, all fixed and hope they are behind me. Bad roof seals, bad hub, bad abs module, a new front suspension (steering rack), and I had an overly sensitive tire pressure monitor.

I do want it lowered to the 120mm but am concerned as many other s240 owners cannot get it to the 120 or the weighting is off.
 

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Wow - that stinks. :sad: Why are they being made this way so the battery can be replaced if needed?
I am guessing it has to do with all the vibration and sudden movement of the wheels while in use. It has to be a pretty harsh environment for the electronics being inside a spinning/bouncing tire and I suppose an exposed battery would eventually become dislodged or lose its connection. Also, most of the compressed air hoses people use for inflating tires add a lot of moisture to the air inside of the tire and it is possible that moisture would start corroding all the electronics as well as the battery.

I still say, what was wrong with cheap and reliable rubber valve stems and a good tire gauge used weekly?
 

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Discussion Starter · #12 · (Edited)
TPMS problem

Well I must say I am impressed that Lotus USA contacted me with helpful information regarding this problem. Apparently I do have three bad sensors - I just needed to be convinced a little bit. Cars are complex machines and inevitably, stuff happens... When problems arise the best anyone can hope for is that the powers that be will pay attention and service can be obtained. I'm now confident my local dealer will be able to correct the problem once I get the car back into the shop...

Tesprit: I do think the TPMS system is a good choice for the Exige. Yeah, it's a step away from simplicity but when you've got a pricey little car zooming around corners with no spare in the trunk it's nice to know you've got a little electronic friend giving you the heads up that you're about to be rolling around on a metal rim. Not all tire failures are going to be slow enough to benefit from the alert but I, for one, see how this could be very helpful at some point.

Hey, why are we all driving around on Macs and PC's when we own Lotuses?
 

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Has anyone found a way to defeat the system? I have the cup wheels, and the sensors will not fit on them, so I get the fault signal all the time. :sad: It get a little annoying after a while.
 

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Has anyone found a way to defeat the system? I have the cup wheels, and the sensors will not fit on them, so I get the fault signal all the time. :sad: It get a little annoying after a while.
Some of the systems can be defeated but not in a "cut the power or yank the receiver box" sort of way. A few of the systems out there (I've seen these on Toyotas) use a sensor that just reads pressure, but most also require the wheel to be spinning at over 15MPH before they will emit a signal. If you have the simple pressure sensors you can build a pipe with end caps out of PVC plumbing with a Schrader valve stem in one of the caps that is just large enough to contain a set of 4 sensors. Before you glue on the final end cap you toss the sensors inside, glue on the cap and when the glue is set, pressurize the sealed tube to 30 psi. Toss the tube in your car and you are good to go. Unfortunately, most cars have the sensors that need to be spinning so this won't work and it is very difficult to disable the receiver that picks up the signals. The systems are Federally mandated so the manufacturers have built them into the cars in such a way that you can't just pull a fuse or disconnect a wire to disable the system. It is also against Federal law to tamper with a TPMS so there are no repair shops or car dealers that will disable the system for you.

As far as your TPMS light goes, they easiest way to defeat it would be to cover the light with a piece of black electrical tape.....not very good looking, but easy and cheap to do. A possible option with your cup wheels would be to obtain a set of sensors that strap onto the rim (many Ford sensors are this type) and work on the same RF frequency as the original sensors. Do you have a photo of one of the original sensors from your car or can anyone tell me which brand of sensors are used on the newer Lotus cars? (My Elise is an '05 without the sensors)
 

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Tesprit: I do think the TPMS system is a good choice for the Exige. Yeah, it's a step away from simplicity but when you've got a pricey little car zooming around corners with no spare in the trunk it's nice to know you've got a little electronic friend giving you the heads up that you're about to be rolling around on a metal rim. Not all tire failures are going to be slow enough to benefit from the alert but I, for one, see how this could be very helpful at some point.
I agree there is some merit to having TPMS on a car with no spare tire in the case of a tire blowout, but the real reason the system is on your car is because the Feds have determined the typical car owner these days is incapable of maintaining proper tire pressures on their cars. The Feds reviewed accident statistics and found a significant number of accidents were due to excessively low tire pressures due to a lack of maintenance. This, coupled with the push for better fuel mileage, ended up in the Federally mandated systems. There is also another problem with TPMS showing you are having a major loss of pressure due to a failed tire. I have actually seen the systems not report the pressure loss instantly and the tire was already flat when the light finally came on.
 

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picture of TPMS, Schrader Electronics

I finally got around to removing a couple of my sensors. Attached are pictures of the Schrader Electronics devices.

They are part of the valve stem, have potted electronics in a plastic shell, and are easy to remove. There appears to be a GM logo although it is not clear if it is that(!) GM.

I am unable to run them in my Cup wheels and am interested in ways of spoofing or removing the flashing lights. I do not mind the lit warning light. I hate the 30 interval where the TPMS error message takes over the fuel gauge.

Michael
 

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I finally got around to removing a couple of my sensors. Attached are pictures of the Schrader Electronics devices.

They are part of the valve stem, have potted electronics in a plastic shell, and are easy to remove. There appears to be a GM logo although it is not clear if it is that(!) GM.

I am unable to run them in my Cup wheels and am interested in ways of spoofing or removing the flashing lights. I do not mind the lit warning light. I hate the 30 interval where the TPMS error message takes over the fuel gauge.

Michael
Those sensors do look similar to some I've seen from Cadillac cars so there is a good chance they are GM (probably Euro GM). Here is a photo of the Cadillac ones:

TPMS GM.jpg

Some Fords also use a similar looking sensor:

TPMS ford1.JPG

What you need to find out is what frequency your originals are emitting and then you might be able to find a set of the sensors that get strapped to the drop of the rim (the part of the rim where the tire bead drops into when removing/installing a tire) and emit the same frequency when activated. The ones from Ford that strap onto the rim look like this and don't have the integral valve stem:

TPMS ford2.JPG

The straps look like large long hose clamps:

TPMS strap.JPG

This is the typical way to maintain a functioning TPMS on a car that is not using TPMS compliant wheels. Will this work with your Cup wheels? Who knows, but with some research and some cheap used sensors from eBay you might be able to find out.
 

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I finally got around to removing a couple of my sensors. Attached are pictures of the Schrader Electronics devices.

They are part of the valve stem, have potted electronics in a plastic shell, and are easy to remove. There appears to be a GM logo although it is not clear if it is that(!) GM.

I am unable to run them in my Cup wheels and am interested in ways of spoofing or removing the flashing lights. I do not mind the lit warning light. I hate the 30 interval where the TPMS error message takes over the fuel gauge.

Michael
Hey Michael, here is your answer to the specs on the Lotus sensors: http://www.lotustalk.com/forums/1216454-post6.html All you need to do now is to find a set of the strapped on sensors with a 433 mhz frequency.
 

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Can you disable the secondary oxygen sensor thru the ECU so you don't get the CEL light with a decat?

I can disable them in the ecu, not the easiest solution but it works.

The batteries are glued in.
 
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