2017 Toyota Tacoma TRD and multiple codes and issues (Tech Stream)

Yes here are the codes currently ALL under ABS in tech stream. I did not have tech stream until recently so I dont know. I know I had no CELs,

They are perm DTC

c1271 - 78
c1281 - 83
c1379

Let me go to that test. Thanks. Be back in 5-10 minutes

 

Interesting, I looked those up and it says they can only be generated when the ABS module is in Signal Check Mode.

 

Ok hopefully did this right. I can go borrow a better DMM, the one I have is a cheapy.

Pin 6 & 14 = 54.5 ohms (what should the value be?
Pin 6 & 14 = ? The value was so high on my DMM it just showed 1 and them when i put it at the max which is 2000k and it had a number but it was moving all over (what should the value be)
Pin 6 & 16 = 6.04k Ohms (whats should the value be)

If I need to and it doesnt sound like my DMM is working correctly Ill go borrow a good one. Thx

 

I did click on that, I was following a Youtube video, and it said to click on signal check mode. Ive never really used the tech stream before. Maybe I screwed up on that. Sorry. So how should I proceed? Thanks again for your help.

 

6 to 14 should be around 60 ohms

6 to 4 should be OL or in the mega ohms
6 to 16 should be OL or in the mega ohms

Can you check voltage between 6 and 4 and then 14 and 4 with the key on battery connected? Should be about 2.5 v

I'm not super familiar with techstream, I have all aftermarket tooling but it essentially does the same stuff.

You said things go nuts when the scanner is disconnected, I was wondering what codes are setting at that time.

 

I can check the codes again. Ok, I checked the pins again using a neighbors better DMM.

Pin 6 - 14 = 53.5 Ohms, mine read 54.5
Pin 6 - 14 = O ohms (didnt beep for continuity), mine didnt show anything
Pin 6 - 16 = O ohms (didnt beep for continuity), mine just showed some initially 6.04K ohm, but Im sure his is more accurate.


Ok, let me go check the voltage.

 

Voltage:

Pin 6 - 4= ~2.7 - ~2.8 volts
Pin 14 - 4= ~2 - ~2.3 volts

 

Without a scope it seems the CAN bus is doing ok.

I guess I need to go back and read the other threads, I'm not exactly sure what we are chasing here.

The codes you listed are check mode codes but I'd like to know the actual trouble codes that are setting.

You said you had communication codes I thought?

 

No just those codes that you indicated that are check mode codes. There is no CEL, let me check to see if anything comes up on the tech stream again.

Here is the video showing what is happening (has been happening for a couple years off and on, now its bad):

https://www.dropbox.com/scl/fi/e957...ey=p3lg0repwfmfn8nut3eczvzdv&st=mm9bcj8b&dl=0


Thanks!

 

Ah ok that looks like a CAN bus problem to me but without being able to scope the CAN signals when the problem is occuring it's gona likely be really difficult to track down.

Any history on the truck around the time this problem started occurring? (Collision damage, flooding/water intrusion, aftermarket stuff installed, repairs, etc).

 

Im actually not sure to be honest, its been over several years. The only add ons are a subwoofer, tied into existing audio and the amp power on is off the window fuse but its been disconnected for these tests, bar light in the front that has a wire tied into the brites fuse that actuates a relay, power comes off a battery, I forgot to add initially that I also have a Viper alarm that was installed and has remote start. Oh, and a module behind the cluster from Rough Country that changed the spedo after putting bigger tires on. Any other additional ideas other than a scope? Thx

 

I need to sit down and look at the CAN bus layout and your other threads tonight.

I'm just looking for clues as to anything related to when the issue started happening and what conditions it happens under like if it only happens when it's wet/raining, hot, cold, certain location, day of the week, etc. Codes it's setting, anything that doesn't work when the problem occurs etc.

Intermittent issues are the worst to track down so the more info and data points we can compile in how to first duplicate the problem and form a game plan on what to test the better.

 

Ok, I went out again to capture codes. Hooked up the obd2 male (the mini that I received) plugged into the vehicles female side. Plugged the USB into the computer, started up tech stream, put the vehicle in ign, nothing, ran a bus check, nothing, no issues. Unplugged the computer side usb for poops and giggles, nothing either. Lost connection but I reestablished connection with the truck. Pulled the obd2 male and the instrument cluster did it again. plugged it back in, left the computer side unplugged not one issue...

 

When it first started it was cold mornings, now, it seems its all the time, wet, cold, hot, dry... doesnt matter. It seem though that the obd2 plug which i never noticed, is doing something. Strange

 

So I saw this on another site, and thought this might play into it? I think you may have mentioned it.

"
The obd connector has 2 grounds. Chassis ground and signal ground. Most scanners, when connected to the obd port will ground on both pins. This will bridge the pins and connect signal ground to chassis ground.

So if your ecm has a bad ground and you plug in a scanner, it will restore its ground through the scanner, and through the chassis pin ground. "

 

That's what I was thinking at first but you said voltage between pins 4 and 5 was 0 which if we had a bad ground I would expect to see voltage between them.

 

So would it be the ECM ground or the Chassis ground issue? If ECM does that wire go directly to the ecm and where is it located and can i check something there?

 

From the tests we did it doesn't appear to be a problem with either of them but I guess to rule it out completely you could put a jumper between them (make absolutely sure your jumpering the correct pins) and see if the problem is fixed.

 

I have a regular scanner that has a regular style plug. I dont think this one has drivers and stuff on a board inside it, it doesnt connect to a computer just a handheld. Im going to plug it i and see what it does, ill back...

 

So it is ok if i jump a wire between them? Let me go check that