'98 Suburban Transfer Case

[dannic]

98" GMC Suburban K1500 Auto Pushbutton 4wd

History...

Service 4wd light came on

Checked fuses - TCASE fue blown

Replaced TCASE fuse

Turn ignition switch on and all four 4wd button lights show at same time for a few seconds

Push buttons and nothing happens

TCASE Fuse is still good

I jacked it off of all four tires

In Neutral the back tires spin, drivers side slower that passengers side.

The axle between front and read Transfer case spins but front tires do not spin at all.

Now What??

[dannic]

One more thing... When I unplug the TCASE fuse and then plug it back in with the ignition off. Then I get a clicking coming from under the dash next to the fuse panel.

[MT-2500]

Originally Posted by dannic

98" GMC Suburban K1500 Auto Pushbutton 4wd

History...

Service 4wd light came on

Checked fuses - TCASE fue blown

Replaced TCASE fuse

Turn ignition switch on and all four 4wd button lights show at same time for a few seconds

Push buttons and nothing happens

TCASE Fuse is still good

I jacked it off of all four tires

In Neutral the back tires spin, drivers side slower that passengers side.

The axle between front and read Transfer case spins but front tires do not spin at all.

Now What??

We need to know which transfer case. 243 or 246.
Both can be checked for codes threw the computer system.
But different ways on getting codes and different set of codes.
Check the tag on back of transfer case and post back what it is.
MT
Codes will point you to the problem.

[gmtech79]

Check for B+ and Ground at the connector for your front axle actuator. As far as the clicking you are just hearing the transfer case control module (TCCM).
Jack the vehicle off of all four wheels and put the trans in drive instead of neutral with either 4HI or 4LO selected and see if the front driveshaft spins but not the front wheels. If it does you know you need to do what I said above.

[MT-2500]

Originally Posted by dannic

One more thing... When I unplug the TCASE fuse and then plug it back in with the ignition off. Then I get a clicking coming from under the dash next to the fuse panel.

If it is a 246 transfer case here is the first thing to start with.

DIAGNOSIS & TESTING

A TC SYSTEM CHECK

Before proceeding with transfer case electronic controls
diagnosis, perform the following test procedure. This procedure checks
Class II communication between Automatic Transfer Case (ATC) control module and scan tool, checks static system operation, and also checks park/neutral switch input operation.
1) Connect scan tool to DLC. Turn ignition switch to run
position (engine off). Use scan tool to communicate with Class II data
bus, A TC control module, Electronic Brake Control Module (EBCM) and Vehicle Control Module (VCM) or Powertrain Control Module (PCM). If communication link is okay, go to next step. If communication is not okay, diagnosis Data Link Connector (DLC) malfunction. See DLC
DIAGNOSIS OR NO SCAN TOOL DATA article in appropriate BASIC DIAGNOSTIC PROCEDURES article:

* BASIC DIAGNOSTIC PROCEDURES - 4.3L
* BASIC DIAGNOSTIC PROCEDURES ~ 5.0L
* BASIC DIAGNOSTIC PROCEDURES - 5.7L * BASIC DIAGNOSTIC PROCEDURES - 6.5L * BASIC DIAGNOSTIC PROCEDURES - 7.4L

2) Using scan tool, check for any DTCs present in Anti-Lock
Brake System (ABS). If any DTCs are present, see ANTI-LOCK BRAKE SYSTEM article in the BRAKES section. If no DTCs are present, go to next step.
3) Using scan tool, check for any DTCs in VCM or PCM, as
equipped. If any DTCs are present, see appropriate SELF-DIAGNOSTICS article in the ENGINE PERFORMANCE section. If no DTCs are present, go to next step.

* SELF-DIAGNOSTICS - 4.3L * SELF-DIAGNOSTICS. 5.0L * SELF.DIAGNOSTICS - 5.7L * SELF-DIAGNOSTICS. 6.5L * SELF-DIAGNOSTICS - 7.4L

4) Using scan tool, check for any DTCs in ATC control module. If any DTCs are present, go to appropriate DTC test. See
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table. If no DTCs are present, go to next step.
5) With scan tool installed to DLC, set parking brake, shift transmission to "N" position, and start and run engine at idle. Read motor/encoder gear position on scan tool while shifting transfer case through all modes, allowing time for system to complete each shift request. If scan tool shows correct gear positions, go to next step. If scan tool does not show correct gear positions, see DTC CO327. 6) With scan tool installed to DLC, set parking brake, shift
transmission to "N" position, and start and run engine at idle. Read gear. position on scan tool while shifting transmission from "N" to

"P", then back to "N" position. If scan tool shows correct gear
positions or requested gear position, go to next step. If scan tool
does not show correct gear positions, see DTC CO357 under DTC TESTS or
TRANSFER CASE WILL SHIFT RANGES WHEN TRANSMISSION IS IN PARK (NV 246)
test under SYMPTOM TESTS for park/neutral position switch diagnosis. 7) Road test vehicle, if necessary to identify customer
complaint (shift from 2H to AUTO to 4WD). Using scan tool, check for DTCs. If any DTCs are present, see appropriate DTC test. If multiple
DTCs are present, always start diagnosis with last DTC displayed. One malfunction can trigger multip/eDTCs. If no DTCs are present, system
is functioning properly.

Good luck and let us know how it goes. And post back any codes you may find.
MT

[George Azzi]

I am having the same problems with my 98 Tahoe, just came from the shop I was told it has CO327 code, and to take it the dealer to have it fixed.

george

quote=MT-2500]If it is a 246 transfer case here is the first thing to start with.

DIAGNOSIS & TESTING

A TC SYSTEM CHECK

Before proceeding with transfer case electronic controls
diagnosis, perform the following test procedure. This procedure checks
Class II communication between Automatic Transfer Case (ATC) control module and scan tool, checks static system operation, and also checks park/neutral switch input operation.
1) Connect scan tool to DLC. Turn ignition switch to run
position (engine off). Use scan tool to communicate with Class II data
bus, A TC control module, Electronic Brake Control Module (EBCM) and Vehicle Control Module (VCM) or Powertrain Control Module (PCM). If communication link is okay, go to next step. If communication is not okay, diagnosis Data Link Connector (DLC) malfunction. See DLC
DIAGNOSIS OR NO SCAN TOOL DATA article in appropriate BASIC DIAGNOSTIC PROCEDURES article:

* BASIC DIAGNOSTIC PROCEDURES - 4.3L
* BASIC DIAGNOSTIC PROCEDURES ~ 5.0L
* BASIC DIAGNOSTIC PROCEDURES - 5.7L * BASIC DIAGNOSTIC PROCEDURES - 6.5L * BASIC DIAGNOSTIC PROCEDURES - 7.4L

2) Using scan tool, check for any DTCs present in Anti-Lock
Brake System (ABS). If any DTCs are present, see ANTI-LOCK BRAKE SYSTEM article in the BRAKES section. If no DTCs are present, go to next step.
3) Using scan tool, check for any DTCs in VCM or PCM, as
equipped. If any DTCs are present, see appropriate SELF-DIAGNOSTICS article in the ENGINE PERFORMANCE section. If no DTCs are present, go to next step.

* SELF-DIAGNOSTICS - 4.3L * SELF-DIAGNOSTICS. 5.0L * SELF.DIAGNOSTICS - 5.7L * SELF-DIAGNOSTICS. 6.5L * SELF-DIAGNOSTICS - 7.4L

4) Using scan tool, check for any DTCs in ATC control module. If any DTCs are present, go to appropriate DTC test. See
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table. If no DTCs are present, go to next step.
5) With scan tool installed to DLC, set parking brake, shift transmission to "N" position, and start and run engine at idle. Read motor/encoder gear position on scan tool while shifting transfer case through all modes, allowing time for system to complete each shift request. If scan tool shows correct gear positions, go to next step. If scan tool does not show correct gear positions, see DTC CO327. 6) With scan tool installed to DLC, set parking brake, shift
transmission to "N" position, and start and run engine at idle. Read gear. position on scan tool while shifting transmission from "N" to

"P", then back to "N" position. If scan tool shows correct gear
positions or requested gear position, go to next step. If scan tool
does not show correct gear positions, see DTC CO357 under DTC TESTS or
TRANSFER CASE WILL SHIFT RANGES WHEN TRANSMISSION IS IN PARK (NV 246)
test under SYMPTOM TESTS for park/neutral position switch diagnosis. 7) Road test vehicle, if necessary to identify customer
complaint (shift from 2H to AUTO to 4WD). Using scan tool, check for DTCs. If any DTCs are present, see appropriate DTC test. If multiple
DTCs are present, always start diagnosis with last DTC displayed. One malfunction can trigger multip/eDTCs. If no DTCs are present, system
is functioning properly.

Good luck and let us know how it goes. And post back any codes you may find.
MT[/quote]

[MT-2500]

Originally Posted by George Azzi

I am having the same problems with my 98 Tahoe, just came from the shop I was told it has CO327 code, and to take it the dealer to have it fixed.

george

quote=MT-2500]If it is a 246 transfer case here is the first thing to start with.

DIAGNOSIS & TESTING

A TC SYSTEM CHECK

Before proceeding with transfer case electronic controls
diagnosis, perform the following test procedure. This procedure checks
Class II communication between Automatic Transfer Case (ATC) control module and scan tool, checks static system operation, and also checks park/neutral switch input operation.
1) Connect scan tool to DLC. Turn ignition switch to run
position (engine off). Use scan tool to communicate with Class II data
bus, A TC control module, Electronic Brake Control Module (EBCM) and Vehicle Control Module (VCM) or Powertrain Control Module (PCM). If communication link is okay, go to next step. If communication is not okay, diagnosis Data Link Connector (DLC) malfunction. See DLC
DIAGNOSIS OR NO SCAN TOOL DATA article in appropriate BASIC DIAGNOSTIC PROCEDURES article:

* BASIC DIAGNOSTIC PROCEDURES - 4.3L
* BASIC DIAGNOSTIC PROCEDURES ~ 5.0L
* BASIC DIAGNOSTIC PROCEDURES - 5.7L * BASIC DIAGNOSTIC PROCEDURES - 6.5L * BASIC DIAGNOSTIC PROCEDURES - 7.4L

2) Using scan tool, check for any DTCs present in Anti-Lock
Brake System (ABS). If any DTCs are present, see ANTI-LOCK BRAKE SYSTEM article in the BRAKES section. If no DTCs are present, go to next step.
3) Using scan tool, check for any DTCs in VCM or PCM, as
equipped. If any DTCs are present, see appropriate SELF-DIAGNOSTICS article in the ENGINE PERFORMANCE section. If no DTCs are present, go to next step.

* SELF-DIAGNOSTICS - 4.3L * SELF-DIAGNOSTICS. 5.0L * SELF.DIAGNOSTICS - 5.7L * SELF-DIAGNOSTICS. 6.5L * SELF-DIAGNOSTICS - 7.4L

4) Using scan tool, check for any DTCs in ATC control module. If any DTCs are present, go to appropriate DTC test. See
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table. If no DTCs are present, go to next step.
5) With scan tool installed to DLC, set parking brake, shift transmission to "N" position, and start and run engine at idle. Read motor/encoder gear position on scan tool while shifting transfer case through all modes, allowing time for system to complete each shift request. If scan tool shows correct gear positions, go to next step. If scan tool does not show correct gear positions, see DTC CO327. 6) With scan tool installed to DLC, set parking brake, shift
transmission to "N" position, and start and run engine at idle. Read gear. position on scan tool while shifting transmission from "N" to

"P", then back to "N" position. If scan tool shows correct gear
positions or requested gear position, go to next step. If scan tool
does not show correct gear positions, see DTC CO357 under DTC TESTS or
TRANSFER CASE WILL SHIFT RANGES WHEN TRANSMISSION IS IN PARK (NV 246)
test under SYMPTOM TESTS for park/neutral position switch diagnosis. 7) Road test vehicle, if necessary to identify customer
complaint (shift from 2H to AUTO to 4WD). Using scan tool, check for DTCs. If any DTCs are present, see appropriate DTC test. If multiple
DTCs are present, always start diagnosis with last DTC displayed. One malfunction can trigger multip/eDTCs. If no DTCs are present, system
is functioning properly.

Good luck and let us know how it goes. And post back any codes you may find.
MT

[/quote]

You need to start a new post on your problem .
This is a old post started by someone else on a different truck.

But your code P0327 points the a encoder circuit or wiring problem.
First check wiring and plug in and then get a repair flow chart for that code and go threw it.
If you do not have a good scanner and electrical test equipment and repair info.
Best to find a good dealer or repair shop.
Good Luck
MT