Codes b0770,b0775,b0780,b0785 indicator circuit short to ground/open

[uk tahoe]

hi all , these came up on a scan which was done to see if any thing popped up with a vibration on pulling off from a stop and traction control comming on while turning still need to short those issues but no lights on dash but these codes keep comming back just seeing if any one has dealt with them ,

B0770 4wd indicator circuit short to ground/open

B0775 four wheel drive high range indicator circuit short to ground/open

B0780 four wheel drive low indicator circuit short to ground/open

B0785 two wheel drive high range indicator circuit short to ground/open

Any help be much appreciated

 

[Doubeleive]

looks like the 4wd switch is bad or the harness is crushed somewhere but I would lean more towards a bad switch.
It's possible this could happen if the switch is not plugged in, if it is plugged in then it's probably faulty.

 

[97YukonNZ]

Yes
If the dash has been out at some stage there is a chance the 4x4 switching has not been reconnected.

 

[wsteele]

Will it switch in and out of 4W when commanded by the switch on the dash?

 

[uk tahoe]

looks like the 4wd switch is bad or the harness is crushed somewhere but I would lean more towards a bad switch.
It's possible this could happen if the switch is not plugged in, if it is plugged in then it's probably faulty.

I've just ordered a new switch from Rock auto as I don't even get the yellow light to indicate which mode I'm in .

 

[uk tahoe]

Will it switch in and out of 4W when commanded by the switch on the dash?

I cant hear any thing , I dont get any lights on my switch either , which now makes me think I'm a getting the slip and traction/abs when steering at times so might be stuck in auto

 

[wsteele]

I cant hear any thing , I dont get any lights on my switch either , which now makes me think I'm a getting the slip and traction/abs when steering at times so might be stuck in auto

Looking at my shop manual for my 2007, most of the diagnostic flow charts end with the TCSCM being replaced, after continuity checking for the light signals, shorts to ground, etc., are eliminated when debugging. The diagnostics is heavy into using the Tech 2 to test things. The replacement of the TCSCM entails reprogramming and a clutch reset procedure, just FYI.

 

[Doubeleive]

Looking at my shop manual for my 2007, most of the diagnostic flow charts end with the TCSCM being replaced, after continuity checking for the light signals, shorts to ground, etc., are eliminated when debugging. The diagnostics is heavy into using the Tech 2 to test things. The replacement of the TCSCM entails reprogramming and a clutch reset procedure, just FYI.

wouldn't there be other related codes? seems like there should be, like U codes indicating a short in the canbus

 

[wsteele]

wouldn't there be other related codes? seems like there should be, like U codes indicating a short in the canbus

In the pages I was looking at for transfer case control, the only codes called out were the body codes he posted. Actually nothing ever comes back to the switch (at least that I scanned quickly). It calls out using the Tech 2 to command the different modes, look for the corresponding action and lights showing on the switch, debugging the continuity to the LED on the switch when lights don’t illuminate and then , “change the module”. I didn’t see any u codes (I can go back and see if I just missed them in the charts), I frankly didn’t see anywhere where it calls out replacing the switch, but again, may have missed it.

 

[Doubeleive]

In the pages I was looking at for transfer case control, the only codes called out were the body codes he posted. Actually nothing ever comes back to the switch (at least that I scanned quickly). It calls out using the Tech 2 to command the different modes, look for the corresponding action and lights showing on the switch, debugging the continuity to the LED on the switch when lights don’t illuminate and then , “change the module”. I didn’t see any u codes (I can go back and see if I just missed them in the charts), I frankly didn’t see anywhere where it calls out replacing the switch, but again, may have missed it.

just seems strange that there would be no other codes, I have the service manual in pdf but it's not linkable so it makes it very difficult when it say's to reference "x" and you cant go directly there and it has 10,000+ pages

 

[wsteele]

just seems strange that there would be no other codes, I have the service manual in pdf but it's not linkable so it makes it very difficult when it say's to reference "x" and you cant go directly there and it has 10,000+ pages

I feel you, the manual seems like it was written so a programmer could code for a robot, versus being written for a human to use effectively.

In the transfer case debug section I looked at, the only codes are B07xx and C03xx, no U codes at all. The one exception is a B2725 which pertains to the switch circuit, if that code is stored, then it sends you down a path to debug the switch (and all paths seem to lead to the switch being replaced if the wiring checks), otherwise it all seems to be centered on an endpoint of replacing the shift control module.

 

[exp500]

Yeah that really sux on the pdf manuals, have to keep a notepad handy.
What you will probably wind up doing is a process of elimination by the troubleshooting guide and codes list. The pick the most likely candidate and further investigate with meter.

 

[uk tahoe]

Right so with new and old switch I can hear the actuator working but on the switch itself I don't get the yellow indicator lights to let me know that in in that mode , the red N lights up on start up .

 

[wsteele]

Right so with new and old switch I can hear the actuator working but on the switch itself I don't get the yellow indicator lights to let me know that in in that mode , the red N lights up on start up .

Pretty much everything I have points to the TCSCM. In the book it says when installing a new TCSCM you will need to program it and do a clutch reset (not sure what the clutch reset is, but likely both can be done with a Tech 2).