ScanGuage 3

Anyone have a ScanGuage 3 on a 2005-06? If so can you help me and see if your ScanGuage correctly monitors your tire pressures? My ScanGuage is reading -14.5psi for all 5 tires(spare have a TOMS sensor?

 

Not the year you are asking, but I can tell you something weird on my SG3. When I look at tire pressure after starting up and before moving, I see numbers like -4,5. It changes to pressures shortly after moving. Sort of odd to me. Maybe a translation function that happens with rotation?


Mike

 

I can tell you, yes, my 2006 spare had a TPMS sensor in it. And when I connect my OBDII dongle (OBDLink MX+) and connect into the TPMS ECU, sometimes I see really weird shtuff, including negative values, but typically when the sensors aren’t reporting back (although the pressure is in Hg or something like that I think?).

If you’re not the original owner of the truck, do you have any evidence the TPMS sensors were ever working? I’m only asking because there’s a single wire in our trucks you can ground-out to short the system so it doesn’t report low tires. A LOT of people ground out that wire, typically behind the glovebox. Maybe try dropping one of your rear tires to 23-24 psi, or deflate the spare, and see if you throw a TPMS light? If not, I can link you to the wire you need to check.

 

My ScanGuage never reads anything other than -14.5psi for my tire pressures. It’s really starting to get annoying.

 

I’ve owned the truck for several years and my ScanGuage correctly read the tire pressures until I had to have my sensors replaced, due to one being dead. I’ve not been able to get it to read since then.

 

It takes a minute or so for the ECU to wake the sensors up and read the pressure.....totally normal.

 

Is it constant though? Like, it never updates, even after a few miles of driving?

The way TPMS sensors work, the battery isn't reading/transmitting all the time. Some centrifugal force is required, i.e. the wheel spinning in a circle at a certain speed, for the battery to engage and power the transmitter. If TPMS sensors transmitted all the time, the sensors wouldn't last more than a year or two, hence the design that requires spinning force to cause battery engagement. To @Tundra234's point, this may be why you're seeing neg pressures. However, I swear the ECU retains the "last transmitted" value on the 2000-2006 and shows that. I'd need to connect to my truck next time I drive it to see what's stored in there. It definitely shows negative Hg pressures if TPMS ECU isn't able to reach a sensor, though. And you'll know it can't reach the sensor because the TPMS light will be flashing (solid light = low pressure, flashing light = comms fail)

If they stay in the negatives all the time, you need to consider that the wrong sensor IDs are programmed in the system and/or someone ground-bypassed the TPMS monitor.

 

Reach out to the company. I did that as I didn’t see the transmission temp which I purchased it for. I had to go into a Xcal mode for the unit to extend out to the ECU for a more comprehensive list of PID’s.

Maybe there is something else you need to do. They were very friendly.


Hope to help,
Mike

 

Yes,it is all the time. It does t matter how long or short of a drive I take it constantly reads -14.5psi. It read correctly prior to replacing sensors, had to replace them due to one being dead and two others with a low battery. I have gone through two different sets from my local discount tire and I just put in a set of DENSOs. I know that the TPMS was not bypassed because the light, on the dash always surfaces a few days after reprogramming the sensors. I just got an Autel TS508, yesterday. I have read all my current sensors and have all of their IDs. I need to pull the sensor IDs off the ECU to see if they match.

 

Solid chance the DiscoTire staff don't know how to program the IDs in, maybe they used numerical vs. hex, or they used a TPMS handheld, and either failed to correctly upload, or they uploaded the numbers on the Denso TPMS sensor box/back of the sensor, but the guy popping the tire cloned the new sensors with the old IDs, causing a mismatch. We've seen far too many people on here use tire chain stores like DiscoTire, NTB, etc. and they just don't know wtf they're doing.

My bluetooth OBDII dongle, paired with the free OBDLink software, allows me to connect into the TPMS ECU and see the IDs programmed into TPMS. Lemme grab a pic from my thread where I show how to erase TPMS codes...

 

So I kinda figured the guys at Discount Tire didn’t know what they were doing, that’s why I bought the Autel TS508. Even though I’m not 100% sure what I’m doing, I did do a ton of research . I have done the relearn procedure and my ScanGuage still won’t pick them up. I did read all the sensors and got the IDs. I then pull the IDs from the ECU, with the Autel, and they matched. I have reached out to ScanGuage, thinking that now it may be an issue with their unit.

 

Ok, so here's what I can show you with a few pics and words in between. With my OBDII reader I can see the codes by having it connect directly to the TPMS ECU, rather than a general OBDII scan. The codes look like this on my reader, and I'm fairly certain the codes are in hexadecimal on the box/tag, but OBDLink prints them out in decimal, more on that in a sec.

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Now, we can see I have 2 TPMS codes set in this case, more on that later also. But see that 'registered ID 1 Code'? Converted to hex, that would be "0x0606B155" which is likely what you'd see on the box and the sticker on the sensor for my truck.

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For the working sensors, the ID will show the current temp, pressure, battery voltage, etc.

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And I'm also able to not only see, but review any existing trouble codes, which would tell me exactly which sensors aren't being heard, so now I know which sensors are toast, and what their ID is, so I can use my TPMS sensor reader to ID the exact wheel if I just want to open that tire, clone the sensor ID to a new one, slap it in, and call it a day. One more note to read after this pic:

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It is - as I proved while compiling all this stuff many moons ago - to clear the codes for, in the case above, sensors with ID2 and ID3. And when you do, you'll never (at least, I never did) see the TPMS light for those sensors again. Potentially even after you replace the sensors with different ones, as I found out the hard way. I think after clearing the codes, you need to follow the process in the Owner's Manual to 'reset' the TPMS system, and cause it to create a new baseline PSI for the tires, so it knows to throw on the light once you get x% below the baseline you reset to. Reset requires starting the truck, then holding the TPMS reset button under the dash until the TPMS light flashes 3 times, then go drive around for 20 minutes to start pushing TPMS data into the TPMS ECU.

Oh, and one other note. Continental makes TPMS sensors. DiscoTire installed some in my spare wheelset, and I had them clone my Denso sensor IDs to the Continental sensors. Worked like a champ. Disco tire counter-jockey told me that's the sensor they typically use, nationally, for Toyotas in our generation, and most cars in general, "they just work..."

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Have you done the 'reset' procedure I just described, which is in the Owner's Manual?

I boxed in the pertinent text in red below, Toyota says you need to do that process when changing tire sizes, etc. Shouldn't cause a comm failure if you don't but ...

I know, I know, nobody reads the fucking manual anymore, but they probably should. If you referenced it for this, then bravo, my friend!

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Oh, and here are the TPMS sensors DiscoTire installed. The ID is printed on it 61C674B1 or 0x61C674B1

It's the Continental REDI-Sensor, model # SE10007 (this part)

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So, I pulled the sensor IDs from the sensors using the Autel. I then pulled what sensor IDs were written on the ECU, also using the Autel. These all matched up. I forgot to change the units of measure prior to pulling them so that’s why they are reading how they are. What OBD2 reader and app are you using to get the info you have?

 

I did not do this with this most recent set of sensors but I did with the prior two sets and it didn’t help.

 

These are the sensors I put in, including the spare. I bought them from summit because I didn’t want to run the risk of getting fake ones on Amazon.

 

Yup, those are correct, and what I currently have installed, and working, on my truck. I bought mine from RA, but both get theirs from legit sources.

 

What OBD reader and app did you use to get the info you posted?

 

It’s the OBD Link Mx+. I have the same one. Try the reset procedure linked above and see what you come out with.

 

I have one of those but it’s been sitting in the box. I never used it since I went with the ScanGuage. I’m going to do that procedure, over lunch, and I’ll let you know what comes of it.

 

Goodluck. I ended up grounding mine because I didn’t want to deal with it.

 

I’m almost to that point but I’m so deep now that I’m determined to figure it out!

 

Pull out your MX+ and download the authentic OBDLink app to your smartphone.

Plug the dongle in, turn the car to ON, but no need to start it. Give it 15 seconds to get acquainted, again you don't need the car running.

Launch the app, tap to connect the dongle and set it up per their instructions. If asked to set a 'default' connection, choose the option "always prompt/ask" so it asks which system/ECU to connect into each time you tap CONNECT ("Generic OBDII" is the default, I think?)

Once connected, in the OBDLink app, download the custom PIDs associated with your truck.

Now disconnect, or just kill the app from running totally in your device. Re-launch OBDlink, and during the connection process choose 'Tire Pressure Monitor' to connect into the ECU, the option list it should give you is below - it may toss out a couple other options allowing you to do diagnostics or whatever, and you should be able to read what TPMS codes it's throwing, and that will tell you what the problem is! Again, here's the list of ECUs/systems MX+ can link into, it defaults to the top, but you can choose any of these...

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PS - I can probably give more details if you get hung up on the steps! LMK if anything is confusing, but provide as much details as possible. Their support team (especially Shubert) is great.

 

So it is showing C2121-C2125 unable to receive data for sensors 1-5. Do the sensors transmit straight to the ECU or is there an antenna that picks up the signal and sends it to the ECU?

 

First off, if you just want to get rid of the TPMS light, clear those codes and it'll go away. But after confirming the light is gone 1-2 days of driving later, be sure to attempt deflating a tire (spare, maybe?) to 20psi or less, then confirm the TPMS light goes solid to warn you about it within a few miles. If not, I'm not aware of a way to restore functionality. Maybe save that for later, if you get frustrated? Try this other stuff first.

Some say the TPMS ECU in our trucks is buggy as shit, this is the generation where TPMS was 1st introduced. I don't think "comm fail" codes are persistent, I assume they'll go away, but maybe you DO need to clear the codes out to make everything start working? Doesn't make sense to me, but ...

If you don't want to do that, here's the thing. The TPMS system consists of:

• TPMS ECU, I think is in the dash area (maybe here, the black box)
• TPMS receiver, which is normally on the roof/ceiling, between the dome rear window (AC, RC) or on the driver's side rear corner of roof (DC)
• TPMS sensors, which are obviously in the wheels
• Obviously all the wiring connecting the ECU and receiver in between
• There is no specific fused circuit for TPMS, it apparently shares power, but the receiver is fed power via the roof wire which runs up the a-pillar, potentially feeding the sunroof, dome lights, or other stuff (not on shared power wires per se, just tossing this out there in case it's shared with, for example, the DOME wire, and you pulled the DOME fuse or something stupid like that)

Clearly your TPMS ECU is online, else you couldn't connect to it with MX+.
Clearly your TPMS sensors in the wheels are sending, else the Autel wouldn't be able to read them.

With my limited knowledge, that leaves me to focus on two things:

1. The TPMS receiver/antenna isn't picking up a signal for some reason, or it isn't powered on and/or the line between TPMS ECU and receiver is compromised/shorted.
2. The TPMS ECU isn't associating ID of the signals sent by the tire sensors and picked up by the TPMS receiver as matching what is programmed in the system.
3. You installed an aftermarket stereo and potentially messed with the 2-pin grey harness in the radio bay on later-models which I think contains the speed signal and tire pressure signal? (pic of grey 2 wire HERE, maybe that's the green/orange-stripe wire there?)

Can you post a picture of what MX+ shows your TPMS IDs are, in decimal (non-alphanumeric, numbers-only) format? Just need to see one or two so I can compare to the Autel. I just want to make sure there's not a typographical/conversion error there.

Also, some supporting documents:

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I will have to plug thr OBDLink back in, I should have some time for that this weekend. My light did pop back up gain so I plugged the autel in. This is the code I got.i then cleared the code and it is showing they are all reading but I know that’s not the case because my ScanGuage isn’t picking them up and I bet the light will come back on.

 

Here are some of the other pics