TPMS module issue on a 2018 4Runner
- Thread starter JAXJeremy
- Start date
ArthurKotb
Member
Anything can go bad, so no telling. I had the A/C compressor go out on my 2012 Corolla and that wasn't cheap to replace. Of course, outside of warranty but not very old. The compressor in my '91 Camry was still working when I donated the car to Good Will in 2020.
Code C2124 Toyota: No Signal from Transmitter ID 4 In Main Mode
Code C2124 Toyota Description
The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the tire pressure of the tires. The measured values are transmitted to the tire pressure warning antenna and receiver on the body as radio waves and then sent to the tire pressure warning ECU. The ECU compares the measured tire pressure values with the tire pressure threshold. When the measured tire pressure value is less than this threshold, the warning light in the combination meter turns on. The tire pressure warning valve and transmitters constantly send radio waves to the tire pressure warning antenna and receiver. Under the conditions below, the tire pressure warning antenna and receiver are unable to receive the signals from the tire pressure warning valve and transmitters, and a Diagnostic Trouble Code (DTC) is stored.
- Facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.
- Devices using similar radio frequencies are used in the vehicle.
- The ID of the tire pressure warning valve and transmitter is mistyped during registration.
- A tire/wheel/transmitter from a different vehicle is installed.
Code C2124 Toyota: No Signal from Transmitter ID 4 In Main Mode
Code C2124 Toyota Description
The tire pressure warning valve and transmitters that are installed in the tire and wheel assemblies measure the tire pressure of the tires. The measured values are transmitted to the tire pressure warning antenna and receiver on the body as radio waves and then sent to the tire pressure warning ECU. The ECU compares the measured tire pressure values with the tire pressure threshold. When the measured tire pressure value is less than this threshold, the warning light in the combination meter turns on. The tire pressure warning valve and transmitters constantly send radio waves to the tire pressure warning antenna and receiver. Under the conditions below, the tire pressure warning antenna and receiver are unable to receive the signals from the tire pressure warning valve and transmitters, and a Diagnostic Trouble Code (DTC) is stored.
- Facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.
- Devices using similar radio frequencies are used in the vehicle.
- The ID of the tire pressure warning valve and transmitter is mistyped during registration.
- A tire/wheel/transmitter from a different vehicle is installed.
ArthurKotb
Member
Just 4? Not replacing the spare? Maybe you're getting them for snow tires?
ArthurKotb
Member
Interesting, I have a 4th gen and it reads the spare too. I don't think it would read a second set, like snow tires, but I'm not sure. I don't have them anyway. You have a full size spare?
ArthurKotb
Member
I had that happen a lot and it's a hassle to get the spare down to put air in it. A lot of people have had problems with the cable and mechanism seizing. Mine did but I was able to get it free. To get the old one off is a real pain too.
I had a very slow leak at the wheel and tire bead. I got a warning light about once a month.
I had a very slow leak at the wheel and tire bead. I got a warning light about once a month.
1000MPH
Senior Member
Yes, full sized spare on a steelie with a rubber stem.
Here’s a Screenshot from TechStream. You would think it will take a fifth sensor but it does not.
Attachments
Sticky?
I'm wondering if this thread should be a sticky. There certainly is a lot of useful information here but there also seems to be some confusion, at least on my part.
Had I known there was a way to make Denso sensors work then I wouldn't have spent the money on genuine Toyota parts. I'm also curious about the Denso's as replacements because sooner or later the batteries in my sensors will run down. Though from reading all this I still don't know if they would work with the system on my '22 Sport. As it was I had the OEM sensors installed on the wheels with my snow tires and once bolted on I reset the system to read the new sensors through the dash display with control buttons on the steering wheel as outlined in the owners manual. Having plug and play snow tires was the primary reason I went with OEM.
What year did fifth gen's change to the system I have?
I'm wondering if this thread should be a sticky. There certainly is a lot of useful information here but there also seems to be some confusion, at least on my part.
Had I known there was a way to make Denso sensors work then I wouldn't have spent the money on genuine Toyota parts. I'm also curious about the Denso's as replacements because sooner or later the batteries in my sensors will run down. Though from reading all this I still don't know if they would work with the system on my '22 Sport. As it was I had the OEM sensors installed on the wheels with my snow tires and once bolted on I reset the system to read the new sensors through the dash display with control buttons on the steering wheel as outlined in the owners manual. Having plug and play snow tires was the primary reason I went with OEM.
What year did fifth gen's change to the system I have?
ArthurKotb
Member
That is awesome that you can get the system to read the TPMS and update the ECU. Denso is OEM. Toyota owns about 25% of Denso. My OEM TPMS are identical to the ones I bought on Amazon. Batteries wear down but I got many years out of mine on an early model 2004. Only one went out last year, 18 years old, 3 were low and 1 was still good.
ArthurKotb
Member
Have you ever had a sensor installed in the spare? Looks like it would certainly be able to read it since there is a space for it. Using my reader I can read the sensors without them being installed in a tire. Does the Techstream have a reader or does it just read them after installation in the tire through the ODB II port?
Is that Techstream running on a laptop? Did you get that off Amazon?
JAXJeremy
New member
Light was off for a while earlier today, drove about 15 miles, when I was almost at my destination it started flashing again and then went solid and now it's doing it every time I get in the car.
[MENTION=701042]ArthurKotb[/MENTION] made the point about the sensor possibly getting jostled into working again..I'm beginning to lean towards this as what's happening.
Even though the battery on the sensors are good there must be some sort of intermittent fault in one of them/
May just bite the bullet and get one of those scanners..
Anyone know whether 2018's have the TPMS in the spare?
[MENTION=701042]ArthurKotb[/MENTION] made the point about the sensor possibly getting jostled into working again..I'm beginning to lean towards this as what's happening.
Even though the battery on the sensors are good there must be some sort of intermittent fault in one of them/
May just bite the bullet and get one of those scanners..
Anyone know whether 2018's have the TPMS in the spare?
ArthurKotb
Member
If the spare has a rubber valve instead of the aluminum one, then there's no sensor there. If the spare is on a steel wheel instead of alloy then most likely it doesn't have a sensor.
Did you try lowering tire pressure on all the tires when the indicator was flashing? If it's sitting there, engine off, key in the run position and it's flashing, lower the tire pressure to 20 psi. If it goes solid, air up that tire and it should switch to flashing. Go to the next tire and do the same thing. If the flashing doesn't stop, that's the problem sensor. Swap that tire with the spare and drive around without the suspect tire to see if the light stays out.
Did you try lowering tire pressure on all the tires when the indicator was flashing? If it's sitting there, engine off, key in the run position and it's flashing, lower the tire pressure to 20 psi. If it goes solid, air up that tire and it should switch to flashing. Go to the next tire and do the same thing. If the flashing doesn't stop, that's the problem sensor. Swap that tire with the spare and drive around without the suspect tire to see if the light stays out.
JAXJeremy
New member
I'll give that a try today. Can't recall whether the spare has a rubber valve or aluminum, but I'll check that as well.
JAXJeremy
New member
The valve in the spare is rubber, so no TPMS there. We can eliminate that from the equation.
I cannot time it to where the lights flashing and I'm able to lower the tire pressure. The light will blink and then go solid. It did last night when I drove home and this morning when I started it up the light was out again..Guess I could just replace all of the sensors, but that seems like a huge waste of $$.
I cannot time it to where the lights flashing and I'm able to lower the tire pressure. The light will blink and then go solid. It did last night when I drove home and this morning when I started it up the light was out again..Guess I could just replace all of the sensors, but that seems like a huge waste of $$.
ArthurKotb
Member
Left untreated, things go from bad to worse. Luck could be on your side. 
I let mine blink from last December to early November before fixing it. You could invest in a TPMS reader ($200 for this one: Amazon.com: Autel MaxiTPMS TS501 TPMS Relearn Tool, 2022 Upgraded Automotive Scan Tool of TS408, TS401, Activate/Relearn All Known TPMS Sensors, Program MX-Sensor [315 & 433MHz], TPMS Diagnostics & Reset : Automotive . It worked for me.) It's a lot to spend just to find out. I'd just let it go and see what happens.
One other thing. If you have someone that could help you out. Put the spare on one of the four wheels and leave that wheel at home. If the blinking continues, it's not that wheel, restore the original to its position. Swap the spare to another wheel and continue. Maybe you'll get lucky on the first try.
If you have a flat, get the friend to bring your tire to you.
I let mine blink from last December to early November before fixing it. You could invest in a TPMS reader ($200 for this one: Amazon.com: Autel MaxiTPMS TS501 TPMS Relearn Tool, 2022 Upgraded Automotive Scan Tool of TS408, TS401, Activate/Relearn All Known TPMS Sensors, Program MX-Sensor [315 & 433MHz], TPMS Diagnostics & Reset : Automotive . It worked for me.) It's a lot to spend just to find out. I'd just let it go and see what happens.
One other thing. If you have someone that could help you out. Put the spare on one of the four wheels and leave that wheel at home. If the blinking continues, it's not that wheel, restore the original to its position. Swap the spare to another wheel and continue. Maybe you'll get lucky on the first try.
If you have a flat, get the friend to bring your tire to you.
JAXJeremy
New member
Was running a bunch errands this morning, maybe 10 to 12 miles of driving total. TPMS light was off to start. This gave me false hope that the problem may have "resolved" itself..Then on my way home, just about to turn into my neighborhood the light starts flashing and goes solid. I'm wondering if I just take it to Toyota whether their equipment will be able to figure it out.
Humble Leader
Senior Member
toyota definitely has the tools to be able to properly program the sensors. if the light is on when you bring it in they would be able to see which sensor isn't transmitting and can replace it
JAXJeremy
New member
Found the offending sensor, drivers side rear.
Was driving today and the TPMS light would pop every time I started back up. I knew the pressure was good since I had just taken it yesterday. Anyway, last time it came on I went up to the tire shop..They were able to get a reading on all the other tires except for that one.
If I recall the last shop that checked said the battery was good in all the sensors, so my assumption is that the sensor itself crapped the bed..
Was driving today and the TPMS light would pop every time I started back up. I knew the pressure was good since I had just taken it yesterday. Anyway, last time it came on I went up to the tire shop..They were able to get a reading on all the other tires except for that one.
If I recall the last shop that checked said the battery was good in all the sensors, so my assumption is that the sensor itself crapped the bed..
