Transfer case dead again!! Please help

[Nova63]

Hi guys,
About 6 months ago I had an issue with this trailblazer. It turned out to be the transfer case motor. I purchased a new Dorman unit from Summit Racing and replaced the old one and everything worked great. Now I have the same issue again!! Indicators at the switch blink when I turn the ign ON, then blink again when starting the engine, then goes out & turn black. Nothing happen when switching modes in Neutral, no clonking, no nothing...

It throws the code C0321 transfer case lock circuit malfunktion dtc status.

I did remove the nr 8 fuse and put it back with no result.

Can it be the transfer case motor again, is Dorman unit that poor quality, its only 6 months old, anyone? I'll hoist the car and start looking, just wanted to hear your opinions first.

Thanks

Matt

 

[Nova63]

When the transfer case motor was dead last time it throws the code C0327

 

[The_Roadie]

What year is it?

I've read a few reports that Dorman makes many reliable replacement parts, but the encoder motor isn't one of them.

It should be possible to troubleshoot the moroe lock circuit to see if it's a TCCM or wiring harness problem. Do you have the schematics and some electrical troubleshooting experience? The encoder motor colenoid lock is just two wires on the harness, and should be easy to see if it energizes when the motor should be allowed to move between 4WD modes.

 

[Nova63]

Year is 2002,

No I dont have the schematics, its the 7 pin type connector to the encoder motor. Im not sure which ones that should have current when engaging the switch. The wiring seems to be roated forward above the transfer case and transmission. Do you know where the other connector is loacted? Im looking at this, either its the TCCM, wiring harnes, ground, encoder motor that fails, so I guess i will start by having someone in the car playing with the switch, while im under there and look for current at the connector.

Last time I did this and found that it was shortage in the wires going into the encoder motor.

Thanks
Matt

 

[The_Roadie]

The schematics are in the manuals available for download by member mooseman. It's also in a sticky thread. Or you can find them in a few seconds by doing a Google image search for "tccm schematics site:gmtnation.com"

As far as I know, there are no connectors between the encoder motor and the TCCM.

Tell me more about the wiring problem you found before. I thought you had a bad encoder motor and just replaced that. Did you have other problems and how did you repair the wiring?

 

[Nova63]

Roadie,
Last time the issue was; Transmission was stuck in low when I got the car. The switch blinked for a sec or two when ign on, then again for a sec or two when starting the engine. I had a buddy in the car playing with the switch while i was under the vehicle messing with the wires going into the encoder motor. I noticed that when I bend the wires going into the encoder motor it suddenly select modes and i was able to switch to high and 2 wheel drive. I unbolted the motor and found that the issue was bad connection somewhere inside it. I ordered a new Dorman 7 pin from Summit and installed it. Everything worked fine.

6 months later samme issue. Ive been away working for a week so I will look at the car tonight.

Selector switch blinks for a sec or two and then turn black, service lamp is on throwing code C0321

Thanks
Matt

 

[The_Roadie]

I think you have flaky wiring elsewhere in the harness from the TCCM to the encoder motor.

 

[Nova63]

Roadie,
Maybe you are right about the flaky wiring, but I was under the car just minutes ago and unbolted the encoder motor to make sure this was not a stuck transfer case issue. Same thing with the motor lose in my hand, no click nothing in the solenoid when turning the switch. I checked the wiring with checking light and it shows (dim light) current at the green wire and (bright light) current, prolly 12V at the blue, it was steady and nothing happened while turning the switch. I unbolted the ground at the frame under driverseat and cleaned it, I checked Nr 8 fuse, and removed it for about 1 min.

Where should you go next? TCCM or, what would be the proper order to troubleshoot from here?

Thanks
Matt

 

[H2Oboy]

Sorry to jump in on this thread but....

I am having what seems like the exact same symptoms as you described. I have an 02 TB with 143,000 miles, went to put in 4x4 and I noticed the lights on the switch were not on. pulled fuse, replaced, and then got service 4x4 light. Guy at parts store said the codes looked like the tccm but couldn't say 100%. Replaced the TCCM went to check. the switch lights now don't light up when starting the car as before, and no service 4x4 light also no 4x4 engagement. Whats the the chances of getting a bad rebuild unit?? vs. a bad encoder motor.

 

[danj]

H20boy

Could it be the 4wd switch in the dash that went bad? I just had a similar problem with my 07. It was stuck in 4lo and I was getting no lights on the switch. I changed the switch and everything started working.

 

[Nova63]

Yes, it can be the switch but I doubt it... I have lights on for a sec when turning the key, it it was the switch I assume it the lights would be dead all the time, but im not sure. It was acting exact the same way when the solenoid motor was fried, but I assume the new one should last more than six months.

H20Boy, check the motor first, they are known to fail. Just get under there and play with the wires going inside the motor while someone turning the switch and see what happens. If it start to go between the modes, then its an encoder motor failure.

Summit have them for around 170 bucks.

Matt

 

[IllogicTC]

DTC C0321
Circuit Description
The transfer case shift control module controls the transfer case lock solenoid. The transfer case lock solenoid is released by being energized. This is accomplished by grounding the lock solenoid control circuit during gears shifts and in the AUTO or adapt mode. Locking action is applied when power or ground is taken away from the lock solenoid. The transfer case motor is prevented from moving. The system is capable of providing a 2HI, 4HI and 4LO lock-up without the need of additional vehicle power to hold the transfer case in these positions.

This DTC detects an open lock solenoid coil, open motor lock control circuit or an open motor lock feed circuit.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0321 Transfer Case Lock Circuit Malfunction

Conditions for Running the DTC

• The ignition is ON.
• System voltage is 9 - 18 volts .

Conditions for Setting the DTC

• The transfer case shift control module tries to unapply, turn OFF, the lock solenoid by grounding the motor control circuit.
• If the module does not sense the battery voltage at the motor lock control circuit prior to applying the motor lock, the DTC will set.
• Transfer case lock output reads back as a high voltage when a low voltage is expected.

Action Taken When the DTC Sets

• All shifting is disabled.
• The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

• The transfer case shift control module will clear the DTC if the condition for setting the DTC is not currently present.
• A history DTC will clear after 100 consecutive ignition cycles without a fault present.
• History DTCs can be cleared using a scan tool.

Appears your encoder is partially dead, the ground needs cleaned, or somewhere in the power systems that solenoid isn't receiving power.

The solenoid should have a resistance of 15-25 ohms, at the motor connector. I'll try finding pinouts.

 

[IllogicTC]

Back with pinouts. The top of the connector is the side with the retaining clip on it. Using this as a frame of reference, there is a pin providing battery power and a pin providing a ground to the lock (the TCCM presents ground to operate it). These are the two pins in the bottom-center -- the harness that connects will have an orange wire and a tan wire which would correspond to these two pins when connected.

 

[Nova63]

IllogicTC,
Thank you very much!! So you mean there should be 15-25 ohms measured between the two "bottom" middle pins next to eachother at the connector. Between the orange and tan wire going inside the solenoid motor? If this value is lower or much higher the issue is inside the motor?

Thanks
Matt

 

[Nova63]

Or do you mean that I should take the reading from the connector on the harness going forward from the solenoid motor to the TCCM?

Matt

 

[IllogicTC]

This would be on the half that's measuring the motor itself, not the connection leading to the TCCM. We're trying to measure the resistance of the lock solenoid contained in the encoder motor assembly.

If the value is out of range, the encoder motor will probably need replaced. It'd be nice to find a source to get specific parts which go inside, rather than having to re-do the whole thing.

 

[Nova63]

I will take a reading with my ohm meter between the 2 pins in the bottom center of the connector. Measure between orange and tan on the cables going into the encoder motor.

The resistance should be between 15-25 ohm. If its not between these values the encoder motor is bad.

Is this right?

Thanks
Matt

 

[IllogicTC]

I will take a reading with my ohm meter between the 2 pins in the bottom center of the connector. Measure between orange and tan on the cables going into the encoder motor.

The resistance should be between 15-25 ohm. If its not between these values the encoder motor is bad.

Is this right?

Thanks
Matt

It would appear right to me. If you can do it with pictures, it'd be a nice way for a second-eyes confirmation that the test was performed properly.

 

[H2Oboy]

Nova63 i agree i feel if it were the switch it wouldn't light up at all when starting. Going to wiggle some wires tomorrow to see if that gets it to move a bit.

IllogicTC, Thanks for the info on the pin outs.

Reading in this post and others i think that the Doorman quality maybe questionable so any suggestions? Heres what i found.

RockAuto- Cardone re-manufactured ($144), and ACDelco re-manufactured ($192), and
Retech re-manufactured ($164), also Doorman($137)

Advanced AutoDorman ($267), Cardone re-manufactured ($203),

Napa Napa solutions ($ 274), and Napa re-manufactured ($ 204)

Summit Cardone re-manufactured ($158), Doorman ($170)

 

[The_Roadie]

The schematic shows that the lights on the switch are a separate set of wires totally from the control part of the switch. The lamp test doesn't display anything useful about the switch function, except if the correct one lights up at the end of the lamp test. And if the lamps don't flash at all at ignition on, then the TCCM is usually dead.

 

[H2Oboy]

hmm... guess i'll test the switch too.

Thanks

 

[H2Oboy]

So,when i hooked up my "New" re-manufactured TCCM and the test light failed to light that could indicate another bad TCCM?

Sorry to jump in on this thread but....

I am having what seems like the exact same symptoms as you described. I have an 02 TB with 143,000 miles, went to put in 4x4 and I noticed the lights on the switch were not on. pulled fuse, replaced, and then got service 4x4 light. Guy at parts store said the codes looked like the tccm but couldn't say 100%. Replaced the TCCM went to check. the switch lights now don't light up when starting the car as before, and no service 4x4 light also no 4x4 engagement. Whats the the chances of getting a bad rebuild unit?? vs. a bad encoder motor.

just wandering how likely this is.

 

[The_Roadie]

Bad TCCM, bad power to the TCCM, or bad wiring to the lamps in the switch. Did the "service 4WD" lamp light up in the instrument panel?

 

[H2Oboy]

on the one i replaced yes on the one i replaced with no

 

[Nova63]

Just done with ohm test on encoder motor, I checked the orange and the tan, wire (they are not the same color at the dorman unit but anyway, i was looking at the stock harness) Its the two in the middle. I got NOTHING! the ohm meter didnt respond at all. I checked it on both ends on a lose wire, make sure it worked though. I also played around with the multimeter looking for resistans between all the 7 pins, just for fun, but nothing...

Perhaps this indicate the "new" dorman unit is dead after 6 months use, great!

Thanks
Matt

 

[IllogicTC]

What's the warranty on those things? Do you still have the receipt?

 

[Nova63]

Illogic, I have the receipt at my Summit log in page, but It doesnt matter due to the horrific shipping price from USA to Sweden. Ill have to ship it back to Summit, and its not worth it. Ill talk to the owner of this car and he'll decide what to do. Stick with 2 wheel drive vehicle or bolt on a new Dorman encoder motor every 6 months...
Anyway, thanks alot for your help and all the info, it really helped me alot!!

Matt