thunder550

iTrader: (70)

MMMkay I'll see what I can do to find a scan tool

vanillagorilla

iTrader: (1)

That's gross man! Wipe off the keyboard when you're done.

thunder550

iTrader: (70)

thunder550

iTrader: (70)

No codes in the TCCM, tech at the dealer told me it's either the switch or something in the motor/actuator thingy in the front diff.

TXARKITEKT

I bet you that it's the 4WD actuator soleniod. Unless you can pull the codes from the t-case yourself, you may have to go to the dealer and have them diagnose it. Good luck!

CHEVRACER83

There Are A Few Bulletins About Connectors Coming Loose... Check Your Connector Tension

Grumpy5.3

iTrader: (14)

i had one, that drove me nuts, and turned out it was the actuator in the front diff. Can you snag one out of a buddys truck and see if it fixes it???

CHEVRACER83

ALSO LOW OIL COULD CAUSE NO TCASE RESPONSE


NP1 NP2 Transfer Case Overheat Insufficient Lubrication - contaminated contamination hi2 hi4 information inoperative lo4 neutral no noise odor oil part performance shift #PI01052 - (04/30/2003)



Models: .




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When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
Transfer case inoperative or noisy.
Examination of drained oil may indicate overheated/discolored or excessive metal contamination.
Disassembly indicates overheated transfer case components.

Recommendation/Instructions:
Install mainshaft kit part # 88996610 which includes an updated oil pump assembly to improve oil pump performance.
Install new snap rings.
Refer to published service procedures.
ADDITIONAL INFORMATION:

The mainshaft kit part # 88996610 contains the following:

12384982: mainshaft
12478084: oil pump assembly
12478087: oil tube
12478088: oil tube o-ring
12478085: oil screen
12478086: connector tube
12478089: tone wheel

CHEVRACER83

Transfer Case Shift Control Switch Indicator Flashes, then Returns to Previous Mode
Circuit Description
The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, (through Motor Control A or Motor Control B, the ground is provided by the opposing Motor Control circuit and then grounded through the transfer case shift control module ground circuit), the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between 4H, AUTO 4WD, 2H, N, and 4L ranges. While the transfer case motor is energized the transfer case shift control module also energizes the solenoid for the transfer case lock. The motor lock is disabled (locking action released) and free turning of the transfer case motor and sector shaft is then allowed.

This symptom indicates a short to ground, short to power, or high resistance in the Motor Control A, Motor Control B, or Lock Solenoid Control circuits

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step determines if any DTCs have set.

Tests for an open or high resistance in the motor windings.

Tests for an open or high resistance in the lock solenoid windings.

This step determines if the module is sending voltage through the motor control A circuit.

This step determines if the module is sending voltage through the motor control B circuit.

This step determines if the reason voltage is not get from the transfer case shift control module to the encoder motor through motor control A and B circuits is due to an open or high resistance in these circuits.

This step determines if the proper 8 V reference signal is coming from the transfer case shift control module.

This step determines if the module is producing the correct voltage through the P, A, B, and C channels.

Tests the encoder signal ground circuit for an open or high resistance.

Step
Action
Value(s)
Yes
No

Schematic Reference: Transfer Case Control Schematics

1
Was the Transfer Case Diagnostic System Check performed?
--
Go to Step 2
Go to Diagnostic System Check - Transfer Case

2
Were any DTC's indentified in the diagnostic system check?
--
Go to Diagnostic Trouble Code (DTC) List
Go to Step 3

3
Turn the ignition OFF
Disconnect the four wire connector at the transfer case.
With a DMM measure the resistance of the encoder motor, and jumper harness by probing motor control A and motor control B circuits.
Is the resistance within the specified values?
0.8-25 ohms
Go to Step 4
Go to Step 11

4
With a DMM mesure the resistance of the transfer case lock solenoid, by probing the lock solenoid control circuit and the ignition 1 circuit

Is the resistance within the specified values?
18-25 ohms
Go to Step 5
Go to Step 11

5
Start the engine and set the parking brake.
Place the vehicle in neutral and depress the brake pedal.
Disconnect the encoder motor connector at the transfer case.
Connect a DMM to the motor control A cicuit at the encoder motor connector, on the module side of the harness
With a scan tool command motor control A ON.
Is battery voltage present?
2 ohms
Go to Step 6
Go to Step 7

6
Withe the encoder motor connector still disconnected. Connect a DMM to the motor control B circuit at the encoder motor connector, on the module side of the harness
With a scan tool command motor control B ON.
Was battery voltage present?
--
Go to Step 8
Go to Step 7

7
Test motor control A or motor control B circuits for an open or high resistance.

Was the condition found and corrected?
-
Go to Step 13
Go to Step 12

8
Disconnect the encoder motor harness from the transfer case.
Test the 8 volt reference signal on the module side of the harness.
Wwas the voltage within the specified range?
7-9 V
Go to Step 9
Go to Step 10

9
Check the voltage on the encoder signals P,A, B, and C on the module side of the harness.

Are they within the specified values?
4.8-5.1 V
Go to Step 10
Go to Step 12

10
With the ignition OFF test the encoder signal gound for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?
--
Go to Step 13
Go to Step 11

11
Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement .

Is the repair complete?
--
Go to Step 13
--

12
Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement .

Is the repair complete?
--
Go to Step 13
--

13
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the conditions for allowing the symtom to re-occur.
Does the symptom re-occur?
--
Go to Step 2
System OK

CHEVRACER83

Diagnostic System Check - Transfer Case
These diagnostic procedures will help you to find and repair automatic transfer case (ATC) system malfunctions. This service category also contains information for repairing ATC system malfunctions. For best results, use the diagnostic tables, and follow the sequence listed below:

Perform the Transfer Case Diagnostic System Check. All ATC diagnostics must begin with the Transfer Case Diagnostic System Check. The Transfer Case Diagnostic System Check determines the following:
- Proper SERVICE 4WD indicator operation

- Ability of the transfer case shift control module to communicate through the Data Link Connector (DLC)

- Existence of ATC DTCs

Refer to the diagnostic table as directed by the Transfer Case Diagnostic System Check. The diagnostic tables will help enable you to diagnose any ATC system malfunction. Bypassing these procedures may result in the following:
- Extended diagnostic time

- Incorrect diagnosis

- Incorrect parts replacement

Repeat the Transfer Case Diagnostic System Check after you perform any repair or diagnostic procedures. This will verify that you correctly performed the repair. This will also ensure that other malfunctions do not exist.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

Lack of communication may be due to a partial malfunction of the Class 2 serial data circuit or due to a total malfunction of the Class 2 serial data circuit. The specified procedure will determine the particular condition.

A fuse failure will cause no communication. This step checks for this condition.

This step determines if the fuse blows due to a short to ground on the battery positive voltage circuit.

This step determines if there is a short to ground in the battery positive circuit causing the fuse to blow.

This step refers to the table for DTC C0306 for further diagnosis if a transfer case mode change is causing the fuse to blow.

The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.

The presence of DTCs which begin with "U" indicates some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Vehicle speed is provided to the transfer case shift control module via Class 2 and can affect the setting of DTC C0300. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.

Perform diagnostics for DTC C0300 and C0305 first before addressing other DTCs. DTC C0300 and C0305 can be responsible for setting other DTCs.

Step
Action
Yes
No

1
Install a scan tool.

Does the scan tool power up?
Go to Step 2
Go to Scan Tool Does Not Power Up

2
Turn ON the ignition, with the engine OFF.
Attempt to establish communication with the transfer case shift control module.
Does the scan tool communicate with the transfer case shift control module?
Go to Step 7
Go to Step 3

3
Turn OFF the ignition.
Check the underhood ATC fuse.
Did the ATC fuse blow?
Go to Step 4
Go to Scan Tool Does Not Communicate with Class 2 Device

4
Replace the ATC fuse.

Does the ATC fuse blow immediately?
Go to Step 5
Go to Step 6

5
Check the battery positive circuit for a short to ground.

Was the condition found and corrected?
Go to Step 2
Go to DTC C0323

6
Start the engine.
Attempt to shift the transfer case through all modes.
Check the underhood ATC fuse.
Did the ATC fuse blow?
Go to DTC C0308
Go to Step 2

7
Select the transfer case shift control module display DTCs function on the scan tool.

Does the scan tool display any DTCs?
Go to Step 8
Go to Symptoms - Transfer Case

8
Does the scan tool display any DTCs which begin with a "U"?
Go to Scan Tool Does Not Communicate with Class 2 Device
Go to Step 9

9
Does the scan tool display DTC P0502 or P0503?
Go to Applicable Powertrain OBD Diagnostic System Check
Go to Step 10

10
Does the scan tool display DTC C0300 or C0305?
Go to DTC C0300 or DTC C0305
Go to Diagnostic Trouble Code (DTC) List