trans rebuilld now scantool issues

[jocko]

recently had the 4L60E rebuilt and it's going fine. However, when I set a "service engine soon" light, I noticed my scan tool would not properly connect to the computer. It "physicall" connects, but can't read codes or anything, it just says "must be connected to the vehicle", etc. Won't power up once connected or anything.

I normally set the pesky P0442 (small evap leak) code and just reset it. But when I went back to the trans shop - had a few "U" codes - one of which was "lost comm with Auto Trans Computer (ATC). And that concerns me.

Anyone every experience anything like those issues?
- Lost comm with ATC
- scan tool no longer working (i may have a bad cable, but ironic it no longer works right after some major work at a shop....) I'm gonna plug it into another vehicle to see if it's working - if it doesn't then just a cable probably.
thanks,
jocko

[clinebarger]

Your truck doesnt have a Transmission Control Module (TCM). The PCM controls the engine & transmission.

U codes can set when you try to start the engine with a low battery and/or the battery gets disconnected when the key is on. Or a module that shares the class 2 serial data with other modules is unplugged with the key on.

Unless the U codes come back dont worry about it.

Im not familiar with generic code readers. But I will try to help, Check for battery power at pin 16 on the Data Link Connector (DLC) if you have no power check for blown fuses in the underhood fuse box.

[jocko]

That's great gouge clinebarger. I'm gonna check that stuff in the next day or so - will get back to you if I find something. I'm still stumped why my scantool isn't working (it's an Actron 9180 (i think)). Will check power in pin 16 and see what it says.

Here are the actual codes I had before the guy at the trans shop cleared them (and the service engine soon light has not returned, yet):

P0442 Small Evap Leak (no biggee, used to it)
P0403 Fuel Level sensor slightly high/open (expected - fuel gauge has been squirrely - was dropping to zero intermittently, now it's reading high)
U1026 Loss Class 2 Comm (this is the one that concerned me - read somewhere that this was an indication of loss of comm between engine controller and trans controller)
U1041 Loss EBCM/EBTCM Comm
U1064 Loss BCM VTD DM PCM 2/or SBM data

Anyway - these could all have been set by the mechanic disconnecting the batt with the key on, and I don't think the U codes trip the service engine soon light - so when I got the recurring P0442, that tripped the light and THEN I noted that I couldn't read codes anymore (maybe a bad cable or maybe low batt voltage/pin 16 - but am hoping it's just the cable) - took it back to the shop and then the trans mech hooked up an $8K Snap-On super duper code reader - THAT'S when the U codes were noted along with the two P codes. Oh well. So far, the service engine soon light has not come back on - but I do know that I still cannot check codes (even for it to tell me there are none) as I still get the "must be connected to the vehicle" when I connect my Actron ScanTool. Will look into this further - thanks very much for your help!
jocko

[truckdude239]

check you cigar fuse under hood probley blown so it wont connect

[clinebarger]

Originally Posted by jocko

That's great gouge clinebarger. I'm gonna check that stuff in the next day or so - will get back to you if I find something. I'm still stumped why my scantool isn't working (it's an Actron 9180 (i think)). Will check power in pin 16 and see what it says.

Here are the actual codes I had before the guy at the trans shop cleared them (and the service engine soon light has not returned, yet):

P0442 Small Evap Leak (no biggee, used to it)
P0403 Fuel Level sensor slightly high/open (expected - fuel gauge has been squirrely - was dropping to zero intermittently, now it's reading high)
U1026 Loss Class 2 Comm (this is the one that concerned me - read somewhere that this was an indication of loss of comm between engine controller and trans controller)
U1041 Loss EBCM/EBTCM Comm
U1064 Loss BCM VTD DM PCM 2/or SBM data

Anyway - these could all have been set by the mechanic disconnecting the batt with the key on, and I don't think the U codes trip the service engine soon light - so when I got the recurring P0442, that tripped the light and THEN I noted that I couldn't read codes anymore (maybe a bad cable or maybe low batt voltage/pin 16 - but am hoping it's just the cable) - took it back to the shop and then the trans mech hooked up an $8K Snap-On super duper code reader - THAT'S when the U codes were noted along with the two P codes. Oh well. So far, the service engine soon light has not come back on - but I do know that I still cannot check codes (even for it to tell me there are none) as I still get the "must be connected to the vehicle" when I connect my Actron ScanTool. Will look into this further - thanks very much for your help!
jocko

U1026 is loss of class 2 serial data communication between the PCM & Transfer Case Shift Control Module (TCSCM). That was from them disconnecting the module on the transfer case while the key was on. The other U codes are from the key being left on & running the battery dead.

Heres a chart for U codes. U1XXX (different 3 digit numder for each individual module). U1024 whould be a TCM communication fault, but your PCM whould not set this code.

The $8000 dollar Snap-On Modus is a joke compared to my Tech II on GM cars & trucks.

I have a Snap-On MT2500 for everything non GM.

I tryed a Snap-On Solus for a month & sent it back.

[jocko]

clinebarger and truckdude, you guys ROCK!

Checked my scan tool on another gm and it worked. remembered the cig lighter comment - checked it while driving, no workie. Fuse blown, changed it, all is good to go now.

Thank you VERY much for your help - I learned a lot and the problem is resolved. Clinebarger, I printed out your gouge and put it in my "keep it" drawer.