2019 tundra bunch of errors, ? Can bus

Left half of my gauge cluster doesn’t work (tach, oil, coolant temp), also getting errors on dash including automatic head light error, dive start control malfunction, trailer brake error, pre collision malfunction.

Wheel slip light is on as soon as the key is turned on, then abs, 4wd, and other lights come.

Check for fuses but didn’t see any out. OBD2 won’t communicate with multiple different scan tools. Truck drives and runs fine.

Any thoughts on where to start? I’m guessing a can bus issue given the multiple things out. Should I take off the dash and start checking wires and connectors? I’m checked all the connectors I can in engine bay. Nothing looks off.

Thanks!

 

Does your dash look like anything in this thread.

https://www.tundras.com/threads/hel...ng-abs-4hi-4lo-etc.110330/page-2#post-3056277

 

I have those lights/warnings but also the tach, oil, coolant gauges just don’t work at all. No oil seems to be leaking near bearings, truck has only 60k miles.

 

Sounds like a fuse is dead somewhere, check the fuses under the dash. I would probably guess it's the body ECU, but if it's only dash bits, I doubt it. From my previous experience my half of my Celica's body ECU died, so door locks, interior light, tail lights, moon roof, gas gauge and temperature were all gone, but my gauges were digital.

 

I checked all the fuses under the dash drivers side and they all seemed good. I guess I have to keep digging.

 

I have had fuses that looked good/toned on a continuity test & been bad. I would replace the gauge fuse.

 

Any lighting mods, like LED conversion?

 

No lighting mode. Mostly stock besides some minor suspension stuff, bed cover, roof rack etc. All that was done over a year ago without issue.

 

Do the RPM and Speed gauges work? They are run on the CAN also.

If you are not getting communication at the DLC (OBD2) port you have a power issue or a short on the bus somewhere.

I would be checking all these fuses that power the network gateway. It’s a “data router” for the CAN network.

Do you have power on Pin#16 of the OBD connector? It’s powered by the OBD fuse.

 

Thanks for the schematic. Yes pin 16 has power. Yes the speedometer and digital speed work fine.

I thought I checked all the fuses, but I’ll see if there are any I missed somewhere.

 

Any other thoughts? I took apart the dash to see if there is anything obvious, signs of animals etc, but it all looks fine. Tach, coolant, and oil pressure don’t work, so I thought of maybe backtracking from there.

 

Got techstream hooked up and it says ECM no longer communicating on the can bus. Any ideas?

Thanks

 

I'm still thinking a fuse to the body ECU is dead. Not sure where exactly this would be located. Check groundson the kick panel on the driver side footwell, nearest to the door.

 

I double checked them, and they all seem fine. Grounds look great too.

 

Techstream info




I’ve been going thought the manual and checking the ECM wiring harness. Get some low resistance levels for pos battery to ground, but I want to check with another multimeter to be sure. Otherwise everything seems to be checking out okay. Checked the related fuses and relays. I can’t figure out anything else wrong.



I tried replacing with a used ECM, but the same warnings came up on the dash immediately.

Any thoughts from people who know this stuff better than me?

 

My assumption would be some external input into the ECM is shorted out and taking the entire ECM down. A sensor or somthing that sends data into the ECM is sending bad signals...

I think this has happened before with the fuel pump control ecu going bad, it causing weird things to the power circuit of the ECM.

If I was to do anything next I would lay under the rear of the truck and just unplug the connector to the fuel pump control ecu that is on the frame rail. Small chance having it unhooked (if its bad) allows your ECM to function properly and communicate. If this is the case replacing the fuel pump control ecu would fix your problem.

It could be some other input or wiring issue somewhere else however.

 

Thanks Jeff, I like that thought and will give it a try.

 

Unfortunately same codes come up with the fuel pump ecu disconnected the same codes come up. I like the idea though. When I get time I may try unplugging more stuff. Not sure what else to do sadly.

 

But did you get connection to the ECM? That is what is important here... being able to talk to the ECM. The codes could be previously exisiting.

 

Good point. I got the same set of warning lights on the dash, but I’ll try and disconnect again and run techstream when I get a chance.

 

Still no connection to the ecu with fuel pump ecu disconnected.

I have a 100ohm resistance between the pos and neg cables with the battery disconnected. I started pulling fuses and and alt-s 5amp fuse is cause the resistance. Does anyone know if the is normal or could be causing some of the issues?
Thanks!

 

OP make an account on Toyota TIS or alldatadiy.com and use the step by step testing to isolate faults on the CAN bus.

At the DLC3 connector pins 6 and 14 (CanH /CANL) is supposed to be >1M ohm with negative battery lead disconnected for 1 min.

Edit: PS the info I have is for a 2010. It's not worth .e posting info on troubleshooting for your 2019. I did get it to a pdf but don't know how share it here.


Alldatatadiy has this info (26 steps of testing to find and isolate shorts/opens) and will help you along with schematics and test steps (use promo code REPAIR15) for $15 off. And it's Cheaper than TIS.
I'm at work on mobile or I try and get it for you.

It'll be worth the $45...

 

PS depending on how broke things are, Techstream if available will test the combination meter functionality? Lights, needles, display values.

 

I’m still struggling with the error codes above. Also, now the speedometer doesn’t work as well. I’ve tried to replace the guage cluster, took off the intake and checked the knock sensors, tried to disconnect the alternator.

I’m leaving the alt-s fuse out because it has a slow draw when plugged in. I’ve tried to look around everywhere for bad wires but all looks good. Can’t think of what to do next.

@Jeff_5_7 you seems to know a lot about this stuff and have been very helpful, have any other ideas I could try?

 

The ALT-S fuse is just power to the voltage regulator inside the alternator. Did you unplug the wiring connection from the back of the alternator? I think its a 4 pin plug connector.

I would be running a health and CAN check in Techstream again. The cluster is fine, you have a power or network issue with some of the ECUs. The Speedometer Signal comes from the ABS Ecu, the other gauges not working from the ECM but the RPM is also from the ECM and you said it was working?

There is a short in the network or bad component somewhere.

Did you verify power to the ECM at the connector? Might try that, the network wont work if the ECU has no power.

 

Yes, I’ve tried unplugging the alternator connector without luck.

The rpm has always been out. The speed was initially working, but has since stopped. I suspect it was when I was disconnecting the main gateway bus to try and figure things out. Currently the fuel gauge and voltage work.

The car drives and runs fine. Key fob, power windows, locks, lights etc work. Cruise, 4wd, trailer brakes etc do not work.

@Jeff_5_7 i think you nailed it with it being a short on the network or shorted component, but I’m having the hardest time trying to figure out which and where. Testing connectors buried behind the dash is hard.

Could I try disconnecting things on the can bus to see if it will communicate with the ecu? The ecu seems to be the only one that’s not communicating. Also trying to figure out if the parasitic draw on the alt-s current is a clue. Maybe completely disconnect the alternator and techstream?

Thank you so much for your expertise!

 

If it’s running the ECM has power because it controls spark fuel ect. It is operating it is just not working on the network.

I might start by looking and testing around the gateway. It’s just a router for the data on the network. The truck has 6 or 7 separate communication circuits and they are all connected to the gateway. One circuit is a direct connection of the OBD port to the gateway, another is the ECM to gateway. For you to get ECM data out of the OBD it has to go through the gateway as a middle man. All ECM network data runs through the gateway and then out down the other lines that need the data.

Might try to verify the CAN circuit between the gateway and ECM is good and not broken.

Same for the ABS and speedo signal going into the gateway, then out to the cluster.

Does the gateway have any DTCs in Techsteam? Like a lost communication with the ECM DTC

 

I think I have checked gateway to ecm connections before without finding anything off, but I’ll check again as I’ve been learning more in this process and may have missed something. I haven’t checked to abs or speedo.

thanks again for your help.

 

@Jeff_5_7 I went through the “ecm communication stop mode” from the service manual and the can bus lines and power lines all check out okay. Bus lines from the ecm connector are 120ohm.

I’ve checked a replacement central gateway too, but same problem.

Communication bus check on techstream seems to list only the ecm as no longer communicating. Could another can bus line still be causing the symptoms?

If it’s some shorted electrical component, should I start checking can communication after pulling fuses one at a time to see if communication comes back?

Sorry for the million questions and thanks

 

Check the voltage on the CAN H and CANL lines. You can do this at the ECM connection or the gateway connection.

It’s a low voltage system, if you see pulses or variance in voltages that’s data movement in the lines. If you see steady voltage that’s means no data transmission. Have the key on when you check.

I think it will read 2.5 volts for no data and look for small decreases in voltage