Service 4wd - but only in 2wd

[Fless]

Like you said, it's best to get a Tech 2 or other capable scanner on it, especially to verify the trouble code that's setting the message.

I know what mine was doing was not what you're experiencing, but mine had symptoms of being in Auto when I'd switch it to 4HI, that 1/2 second or so lag while the front diff actuator engaged. The 4HI mode light on the switch would light, 4HI was commanded (per the Tech 2), but the actual mode was Auto (again, shown in the Tech 2 at the same time). It had no codes. Turned out to be the encoder motor, like @Sam Harris.

 

[SnowDrifter]

Like you said, it's best to get a Tech 2 or other capable scanner on it, especially to verify the trouble code that's setting the message.

I know what mine was doing was not what you're experiencing, but mine had symptoms of being in Auto when I'd switch it to 4HI, that 1/2 second or so lag while the front diff actuator engaged. The 4HI mode light on the switch would light, 4HI was commanded (per the Tech 2), but the actual mode was Auto (again, shown in the Tech 2 at the same time). It had no codes. Turned out to be the encoder motor, like @Sam Harris.

Well

I guess now:

1. how much a tech 2 costs (I'm seeing a wide spread from 100-500)

2. where to get one that isn't a horrid knockoff and actually works (concerns from above)

3. Cost / feature differential between tech 2 and a much more general purpose shop scanner. I'm open to suggestions on this one

3a. Google poke is nonconclusive for... anything. Harbor freight's Zurich makes me sus, house brand stuff. Unclear if it requires the subscription to function, or if it's only for 'up to date' info. Autel's website doesn't have any comparison tool I could find. And what I could locate on google gives redundant info (if they all work, why the price difference?) Snap-on / matco / etc are immediate price-out

3b. Would want to stay in the <600 range, with no need for subscriptions for diagnostic / 2way comm use. Could stretch to 800 if there's a *really* strong proposition, but not a dollar more.

3c. Would want good and proper 2 way communication. Actuation of various bits and bobs / calibration(abs bleed, actuators, BMS learning, keyfob, TCCM relearn, etc). Also comprehensive live data - relavent to current thread. Concern is advertising vs. fuctionality. I don't care about seeing data from O2 sensors. I want proper positional / actual time / whatever the hell else data. Anything less than that - it's an expensive code-reader and not worth the cost to me.

3d. Oscope, current clamp, etc functionality would be great to have, but not worth a thousand bucks if that's what it costs.

3e. Used is just fine!

 

[George B]

I will just put this here:

Tech 2 Purchase

Time to buy a Tech 2 ..I see a ton of threads when I do a search units clones vs. originals ETC... Where is the best place to purchase? Are there accessories I should be looking at in addition to the unit? Is it even possible to buy a non-clone unit? TIA

www.tahoeyukonforum.com

 

[Fless]

In addition to the thread @George B posted, if you haven't yet read this 3-page thread, it might clarify a few things for you.

Migration from ACDelco TDS to GM Techline Connect for Tech 2 Users

Hi Folks, As you probably know, ACDelco TDS (TIS2Win) site for Service Programming Software (SPS) has been retired, effective September, and current subscription holders need to migrate to its replacement GM Techline Connect. Below, I offer you the process that I used to perform this...

www.tahoeyukonforum.com

Chinacardiags (I think I have that spelled correctly) seems to be a good place to buy a Tech 2; it's where I got mine. You can get them with/without a case for prices between $270 and about $350. You can program (free) your NBS modules with the TIS2000 software included as long as you use a WinXP computer or a Virtual Machine running XP. But that takes a bit of persistence to accomplish; not impossible, but will take some research. Personally I have an old XP laptop that I've dedicated to this instead of the VM path. Otherwise you can pay the VIN fee for Techline and do it online using Win10 as noted in several of the posts on that thread.

Others here will have more recommendations, I'm sure.

 

[Udaman21]

I had this happen a few times. Always happened after it rained or went thru a puddle. Took off the shift motor and torn it down. Found water in the unit. Seals failed. Bought a new sensor and sealed the unit with RTV. Problem solved.

 

[V327839]

I forgot the codes I pulled when something similar happened to me. I replaced the encoder ring easily and cheaply. That fixed the main issue. A later issue is with the speed sensors. They detect the moment of the front and rear driveshafts. They are also cheap and there are two on the tcase. They are identical and just screw in. Might look into those as well. I have a bad front sensor which won’t let me shift OUT of 4hi, but worked fine during the last snow storm for now. Go figure.

 

[2591tdj]

Search this forum for the topic “Service 4WD”. There are a number of discussions and solutions to this all too common problem. Mine was also due to the encoder ring which is an easy and inexpensive replacement.

 

[06 Taco]

I had a similar problem on my 06 Tahoe Z71. Check the grounds that are under the driver side B pillar. Check all the plugs and connections on the transfer case shifter motor and the front axle solenoid. I believe that there are threads on this site that will give you the proper resistance readings for the different pins. There is definitely info on you tube.

 

[SnowDrifter]

Well

Grounds / connections all looked OK. Pulled them off, sanded down, dielectric grease, and some water proofing on top. Removed the plugs and noted no corrosion in the pins. No change.

Ordered the sensor ring based on a best educated guess. I really should get a proper scanner..... But every time I look at the price, I just think to myself: Ok but do I really *need* it.

Will update the thread later with outcomes.

 

[S33k3r]

Well

Grounds / connections all looked OK. Pulled them off, sanded down, dielectric grease, and some water proofing on top. Removed the plugs and noted no corrosion in the pins. No change.

Ordered the sensor ring based on a best educated guess. I really should get a proper scanner..... But every time I look at the price, I just think to myself: Ok but do I really *need* it.

Will update the thread later with outcomes.

What price are you seeing? I finally buckled down and got one after 4 years... I'd suggest against waiting that long.