Hey guys, I’m having an intermittent nagging issue with the drivetrain and I just can’t seem to get to the bottom of it. First, I have a 2007 Tahoe 5.3L with the standard 4L60E trans. Sometimes when I hop in and start it, everything is fine, but half the time the CEL comes on, DIC indicates “Service 4wd” and the transmission will be in “Limp mode.” I have visually checked the drivetrain and changed all the fluids from the front diff to the rear diff. I have taken it to a transmission shop and they just throw parts at it that’s costed me $1500 already. They changed the electronic 4wd actuator (unnecessarily), the ignition switch, and performed the TCC re flash service bulletin upon my request from past research. It was good for about 6-8 months after the service bulletin was completed but now it’s back to the same old issue. Please help! I’m tearing my hair out here. Thanks in advance!
4WD service light and “Limp mode”
- Thread starter gsxrkid
- Start date
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Not reduced engine power, just R and 3rd gear(s) only. I am going to scan the codes again today.. I’ll update on that shortly. The transmission shop cleared all stored codes before this started happening again though.
You need a scanner that can get all of the codes from the TCM, BCM and ECM. A tech2 is a wise investment for any owner of these rigs.
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Sent from my iPad using Tapatalk
Having the same issue, and cant drive the truck for the past few months due to this, kindly update if you found out the reason behind this
So far replaced the actuator, 4wd switch, TCM.
Now checking the wiring harness, maybe a mouse was hungry ? and next would be the fuse box
Also a new battery just incase, but the old one was dead anyway
So far replaced the actuator, 4wd switch, TCM.
Now checking the wiring harness, maybe a mouse was hungry ? and next would be the fuse box
Also a new battery just incase, but the old one was dead anyway
May or may not be your issue, but when mine did this it was an issue with the AFM. One of the lifters wasn't "waking up" when going from V4 to V8. It was stuck and had to be replaced. After that, I had to AFM programmed out.
I had BlackBear tune it years back and he disabled the Displacement on Demand system. It’s permanent V8 mode. Thanks for trying to help though!
Update in case anyone else was wondering, I ran out of all my options and broke down and had it towed to the transmission shop again. They’ve had it for a week and a half already. Been through the troubleshooting process and completed a pin to pin diagnostic test from the computer to the 4WD system. I think they are also still stumped..
after months of trouble shooting the issue, the mechanic confirmed that it was the transfer case control module or tccm, He informed me that he 'borrowed' it from another car he's been working on and it eliminated the issue completely and he test drove it for a day and the issue was actually fixed.
So my next step is to try to figure out why it broke and hope to fix it otherwise i'll need to squeeze about 250+ USD to replace it with a reman. I will update this post once I actually fix it for real or find it in a junk yard
Good luck
edit: this is what i need to replace to fix my issue apparently....
DORMAN 599112
So my next step is to try to figure out why it broke and hope to fix it otherwise i'll need to squeeze about 250+ USD to replace it with a reman. I will update this post once I actually fix it for real or find it in a junk yard
Good luck
edit: this is what i need to replace to fix my issue apparently....
DORMAN 599112
$250 is just regular maintenance money, or a couple tanks of gas. Buy the part and replace it. What’s stopping you?
And they can be found for under $200 (after you return the core); use your Google Fu.
