SOLVED! Hard steering in 4x4

[Daniel644]

OK, here's a weird one (truck is a 03 TB LS with the 4.2). 4WD worked when I bought the truck, used it once or twice over the years during the rare snow storm, got the driver side front axle replaced A few years back now and the next time I can recall switching the truck into 4 Hi after that (while doing about 20 MPH or so was in my neighborhood so wasn't going to fast) the Service 4WD light came on and it became almost impossible to turn the steering wheel (like worse then a car with power steering that has completely failed and the belt is still attached), took all my might to turn onto my street, I was able to get it out of 4WD after pulling the fuse under the hood that forces the reset of the TCCM. Some time after that I tried it again and the same thing happened and it took several pulls of the fuse to get it out of 4WD that time. So I said OK my 4WD is broke and just decided to not use it, fast forward to last year, i'm replacing the rubber brake lines on all four corners, we've got the front end up in the air doing the front brake hoses, I switch it into 4 hi but the wheel turns easily but the service 4WD light did come on but it shifted out of 4WD without having to pull the fuse, but I did pull the fuse to clear the light, fast forward to just now, I decide to run up there and listen to see if the actuators could be an issue, I hear clearly both actuators and it successfully goes into A4WD and 4Hi, crank the trunk and take it for a spin around the block, steering is stiffer then 2WD so I know 4WD has engaged but as I drive it it feels like the steering is getting stiffer, not as bad as it had been before when the 4WD Service light came on but much stiffer then it was when I first rolled out of my driveway in 4hi a few minutes before. What could cause the steering to get harder to turn? Good news, it easily came out of 4WD this time, no fighting with the fuses and no Service 4WD light. when it starts doing this it also takes more throttle to get the same amount of movement, it's almost like something is seizing up slowly when in 4WD.

Anyone ever experience anything like that?

 

[Mooseman]

It's normal for steering to be hard and getting crow hop while turning in 4x4 and on solid asphalt. The system gets bound up without any give in the wheels to allow for different front and rear wheel speeds which happens when you turn the front wheels. 4x4 should only be engaged on loose dirt, gravel or snow. Even wet asphalt is not enough slip.

 

[Daniel644]

It's normal for steering to be hard and getting crow hop while turning in 4x4 and on solid asphalt. The system gets bound up without any give in the wheels to allow for different front and rear wheel speeds which happens when you turn the front wheels. 4x4 should only be engaged on loose dirt, gravel or snow. Even wet asphalt is not enough slip.

I'm not sure if I wasn't explaining it right, it's not that it just has trouble turning, it take more throttle to get it to roll, it's like the parking brake is almost fully engaged, how it was acting right at the end of the drive was different then at the start of the drive.

anyways none of that explains what could have caused the service 4wd light and require the removal of the fuse to get it to come back out of 4wd that it had done several times before or why it didn't do that this time.

I think i'm gonna check the fluid levels and maybe go ahead and change the transfer case fluid again, I did it when I serviced all the fluids years ago when I bought the truck but i've had the transmission replaced since then and i'm not 100% confident they used the proper Autotrak II in the transfer case because I remember having to order it online because none of the local stores stocked it at the time (which wasn't more then a year or 2 before the transmission replacement) and I think they had to drain the transfer case to swap it to the new transmission.

 

[Mooseman]

it's not that it just has trouble turning, it take more throttle to get it to roll, it's like the parking brake is almost fully engaged

Yep, that's part of the crow hopping and binding.

You would need to be able to scan it with a capable scanner the next time the service 4x4 light comes on. It sounds like it could be the sensor in the encoder motor.

 

[Daniel644]

scan it with a capable scanner

I have an OBDLink MX+ and a smart phone or a laptop with bluetooth that the MX+ can be paired to, is there any software that can do it with that equipment? I found a thread from google on the "old site" where the user Blurry talks about scanning the TCCM and getting Hexadecimal codes, but that was from a decade ago, so not sure if anything easier has come along since.


Edit: Just did another test to make sure the 4WD still engaged and I noticed something so I made a quick video:

In the video what i'm doing is I have the 4WD in 4Hi, I have my foot on the brake and I start turning the steering wheel back and forth, this noise sounds like it's coming from the rear of the vehicle, the sound is from the beginning till about 20 seconds in then again from 38-39 seconds to 49 seconds and just a hair at the end second or 2.

Any chance the transmission mount could allow the transmission to shift slightly causing a binding issue?

 

[azswiss]

Using the MX+ with an app like Torque Pro will give you current (active) codes. However, I am not sure if it will give you visibility into immature, pending, or historical codes.

Using a serial terminal program you can interrogate the system directly. You will get hex codes; decoding them is pretty straightforward.

Here is some sample transfer case DTC data I got scanning my '03 Suburban:
6C F1 1A 59 43 21 01 BF

The DTC info is contained in 5 & 6. In this example they are 43 & 21.

The first character in byte 5 determines the DTC prefix (see table below):

0 - P0 Powertrain Codes - SAE
1 - P1 Powertrain Codes - Mfg
2 - P2 Powertrain Codes - SAE
3 - P3 Powertrain Codes - Joint
4 - C0 Chassis Codes - SAE
5 - C1 Chassis Codes - Mfg
6 - C2 Chassis Codes - Mfg
7 - C3 Chassis Codes - Reserved
8 - B0 Body Codes - SAE
9 - B1 Body Codes - Mfg
A - B2 Body Codes - Mfg
B - B3 Body Codes - Reserved
C - U0 Network Codes - SAE
D - U1 Network Codes - Mfg
E - U2 Network Codes - Mfg
F - U3 Network Codes - Reserved

For this example the 1st character of byte 5 is "4"; from the table that translates to "C0".

Now, take the second character from byte 5 ("3") and both characters from byte 6 ("21") and append them to the DTC prefix to get the complete DTC. The result is "C0321" - Transfer case lock circuit malfunction.

Byte 7 is the status code (MIL, Current, Pending, Historical, Immature). Some additional translation is required on this one. Reach out if you need more info.

 

[Mooseman]

Torque Pro can only do P codes so won't work for any other types of codes like ABS and TCCM.

Apart from the method @azswiss explained above, there are also a couple of other apps that may work like Car Gauge Pro and Chevrosys to pull those codes. From past experience, the codes have to be active (service 4x4 light on) to be read.

 

[Daniel644]

Would ATF in the transfer case explain any of these issues, because I just drained it and it came out RED, forking lying mechanic said yes when I asked them if they put Autotrak 2 in it when they replaced the transmission.

Just refilled it with the Autotrak 2, should I do another drain and fill to help flush out that ATF a little more after some miles?


Also I bought some 75w-90 for the front dif but i didn't look closesly at the picture and it has the limited slip additive, is that safe to use in the front dif or should i send it back and get the non limited slip stuff?

 

[Mooseman]

I think you'll be fine with the one fill. I wouldn't be surprised if it's ATF with blue colouring. For the diff, yeah, the friction modifier won't do anything to the front or rear diff.

 

[Daniel644]

OK, now i'm even more lost, I went to my nephews house for a visit and they have a gravel driveway, I flip it into A4WD and then to 4Hi, BOTH A4WD and 4Hi lights stay lit on the switch and the service 4WD light comes on and it doesn't switch back to 2WD when I turn the switch back to 2WD, I shut the truck off then turn the key back to the Run position and I hear the encoder motor switch back to 2WD and the Service 4WD light goes away, not wanting to push my luck I wait till I get home and it cycles thru all 4WD modes just fine without tossing any Service 4WD lights.

I'm not sure what to look at next, the Chevrosys app won't read anything but the PCM codes, it acts like its trying to read the TCM but just says like "unrecognized" or something like that.

 

[Mooseman]

Try the Car Gauge Pro app. I know that one works, albeit with a clunky interface. You have to do a Scan All under GM.

Sounds to me that the encoder motor itself is working but the sensor in it isn't. We have a thread that talks about it and bench testing it.
Transfer Case Bench Testing NP226

 

[azswiss]

Here is a list of TC encoder related DTC's:
C0327 Encoder circuit malfunction
C1499 Transfer Case Contact Plate "A" Encoder Circuit Failure
C1500 Transfer Case Contact Plate "B" Encoder Circuit Failure
C1501 Transfer Case Contact Plate "C" Encoder Circuit Failure
C1502 Transfer Case Contact Plate "D" Encoder Circuit Failure
C1856 Traction Motor Encoder circuit Failure

 

[Daniel644]

Try the Car Gauge Pro app. I know that one works, albeit with a clunky interface. You have to do a Scan All under GM.

Sounds to me that the encoder motor itself is working but the sensor in it isn't. We have a thread that talks about it and bench testing it.
Transfer Case Bench Testing NP226

you weren't lying, that is one clunky app, didn't show any current codes (since the light wasn't lit) so I tried History Codes and it gave the C0327 code then for the hell of it I tried Intermittent Codes which gave quite the list:

C0300
C0305
C0306
C0321
C0327
C0359
C0374
C0379
C0550

and then several Body codes. I'm gonna google these codes, it's also throwing a code for coolant temp to low, likely due to the 175* thermostat I put it in years ago, will probably swap that out once summer is over so it will warm up faster/more in winter.

Also I have screenshots if you think the body codes might be related, like maybe a common ground point or something that would explain an intermittent electrical issue.

 

[Mooseman]

The C0327 alone tells us there is something wrong with the circuit. We have a thread on this with a lot of leads to follow. Unfortunately the OP never came back to conclude it.

NEED HELP - Transfer case encoder co327 problems

Hello everyone. I'm seriously in need of some answers about my 2006 chevy trailblazer EXT LT 4.2L I6. So we came back from camping and a couple days later we had the service four wheel drive light come on. I had the truck scanned at a mechanic shop and came back that my decoder motor was non...

gmtnation.com

If you have a pick-a-part nearby, I'd grab a TCCM (03+) and swap it out just to eliminate that. I'd also grab a switch or at least give yours a good back and forth workout to clean the contacts.

You should give the wiring a deep check with all those codes, some pointing to shorts and circuit problems. Check all continuity and each for shorts to ground and/or each other. Maybe wires got chewed by rodents or abrasion somewhere wore the insulation just enough to intermittently cause a short.

 

[Daniel644]

@Mooseman back when these problems all started a few years ago the first thing I tried was replacing the switch, it behaved exactly the same way after replacing it with a new part from the parts store.

as for the TCCM, after seeing it's location I have to consider that a possibility of issue as i've removed that panel under the steering wheel on several occasions. don't have a local pull a part and seeing used ones on Ebay for as low as like $50 it would probably be best to try the Ebay part then to spend the 20-25 in gas and 3-5 hours to drive to a pull a part (and potentially a second one if the TCCM isn't in the one at the nearest yard, nearest yard only has 1 03-05).

probably start with that then if issues persist start tracing wiring, i've not seen any signs of rodents anywhere on this truck but can't rule out like a pinched wire somewhere as i've seen other people have causing 4WD issues.

EDIT: Old TCCM removed to get the part number, used replacement unit ordered from Ebay, hopefully will be here by Saturday. no visible signs of component failure on the side of the board I can see of the old unit.

 

[Daniel644]

OK, Replacement TCCM from Ebay installed, Tested on pavement and cycles through all 4WD modes, will have to do further testing to see if that resolved it.

did a quick scan using the Car Gauge Pro app and the History code of the C0327 is gone but all the intermittent codes are still the same, can't see a way to clear them.

Also I just noticed these wires (see picture), they come out of the same main harness that feeds the connectors for the TCCM as a distinct separate pigtail, anyone know what they would go to? Maybe an option this truck doesn't have since it's an LS, kinda odd not to at least have a connector on the end of them and just some electrical tape wrapped around the ends.

Edit: OK several hours later, went out to my sister in laws to help her dad with a misfire on his Trailblazer, while there I shifted in and out of the different 4WD modes several times over several crank cycles and drove around in the grass, shifted modes every time with no issue. Time will tell but so far issue seams to be resolved with a new TCCM.

I also scanned a Sierra (early 2000's body style) with the push button 4WD that belonged to her grandpa that has 4WD issues and have some ideas from google to try to fix that one.

 

[Mooseman]

Also I just noticed these wires (see picture), they come out of the same main harness that feeds the connectors for the TCCM as a distinct separate pigtail, anyone know what they would go to?

They're for a trailer brake controller. If you follow that bundle, you'll see the label (as seen in the pic) that has the wire colours. They all came like that.

Glad you got it resolved.