2019 tundra bunch of errors, ? Can bus

@Jeff_5_7 canh and canl are both fixed at 4.156V and only fluctuate .003V. No continuity with ground on either line.

 

Interesting, I was expecting 2.5V on each line. My bench setup is 2.5v and drops down to 2.3v when a messages comes. This is from a 2020 ecu network.

I feel like the 4.156v is high.

Are you still also not getting communication from the ABS ecu? You said no speedometer operation

 

@Jeff_5_7 I’ll have to look into the higher voltage. ABS did not give an error in the can bus check on techstream, but I didn’t check it any other way. I do not have speedometer, but I previously did before I started messing with things trying to figure out the problem. Not sure why it stopped working, but I think it happened after I unplugged the gateway trying to figure out the problem. I tried a loaner gateway to see if that would work, but had the same issues.

Do you think it still might be a sensor short? Do most of the engine sensors get to the ecm on the d74 connector. If I remove that and keep A24 connected to see if I can communicate with the ecm through techstream?

I tried removing fuel ecu connectors near the back of the truck but it didn’t change, with the car still able to run fine, I can’t imaging it being a critical sensor.

also, could the parasitic draw from alt-s and the elevated can bus voltage be related? I still have the alt-s fuse removed which stopped the draw yet the battery seems to charge fine.

 

Are you sure it is the AltS fuse then?

 

@Jeff_5_7 I pulled fuses until the draw went away and alt-s worked. It use to drain my battery in a few days, with the fuse out I no longer have the battery drain, but it still seems to charge fine. Voltage is one thing that works on the gage cluster and it sits right in the middle with the truck running.

Should I maybe plug it back in and try other fuses?

Thanks!!

 

Have figured out the cause of this fault ' lam suffering the same problem with my 019 Toyota tundra

 

@Mali8080 Unfortunately not yet. I have only had sporadic bits of time to try and troubleshoot, but it’s getting frustrating. Fortunately the car runs so I can use it.

let me know if you figure anything out.

 

I have the AC module replaced with used one and problems solved.

 

@Mali8080 was your ac working? How’d you figure it out?


Thanks!