Transfer Case - Nvg 263-NP1 (Selectable): Overview — Chevrolet Silverado 2500 (2000-2004)

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

2) - 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.
3) - The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.
4) - The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
5) - Vehicle speed is provided to the transfer case shift control module via Class 2. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.

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

2) - This step tests for proper operation of the transfer case shift control switch.
3) - This step tests for proper voltage supply to the transfer case shift control switch.
4) - This step tests the transfer case shift control switch for proper resistance values in all switch states.
5) - This step tests the 4WD switch signal circuit for a short to voltage.
6) - This step tests the 4WD switch signal circuit for an open or short to ground.
7) - This step tests the 4WD switch signal circuit for a short to the 8 volt reference circuit.
8) - Determines whether the 8 volt reference circuit is greater than or less than the specified voltage.
9) - This step tests the 8 volt reference circuit for a short to voltage.
10) - This step tests the 8 volt reference circuit for an open or short to ground.

Scheme 216

Scheme 217

The number(s) below refer to the step number(s) on the diagnostic table.

2) - Listen for an audible motor noise when the transfer case encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3) - This step tests for a short to ground in the motor control A circuit.
4) - This step tests for a short to ground in the motor control B circuit.
5) - This step tests for a higher than normal resistance in the motor control A and B circuits through the module.
6) - This step tests for a short to ground in the transfer case encoder motor windings.
7) - This step tests for continuity across the motor circuit. Resistance readings vary depending on the location of the brush contact inside the motor assembly.
8) - This step tests motor control A circuit for a short to ground.
9) - This step tests motor control B circuit for a short to ground.
10) - This step tests motor control A and B circuits for an open or high resistance.

Scheme 218

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

2) - Listen for an audible motor noise when the transfer case encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3) - This step tests motor control A or the transfer case shift control module for a short to voltage.
4) - This step tests motor control B or the transfer case shift control module for a short to voltage.
5) - This step tests motor control A circuit for a short to voltage.
6) - This step tests motor control B circuit for a short to voltage.

Scheme 219

The number(s) below refer to the step number(s) on the diagnostic table.

2) - Listen for an audible motor noise when the transfer case encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3) - This step tests the for a higher than normal resistance in the motor control A and B circuits and through the module.
4) - This step tests the motor control A circuit for an open or high resistance.
5) - This step tests the motor control B circuit for an open or high resistance.
6) - This step tests for continuity across the motor circuit.

Scheme 220

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

2) - Listen for an audible motor noise when the transfer case encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
3) - This step tests the motor ground circuit for an open.

The number(s) below refer to the step number(s) on the diagnostic table.

2) - This step tests the operation of the system.
3) - This step helps determine if the encoder motor has supply voltage.
4) - This step tests the encoder channels for proper reference voltage.
5) - This step tests the encoder channels for an open or a short to power.
6) - This step measures the voltage from the 8 volts reference circuit to the encoder signal ground circuit.
7) - This step tests for two or more encoder signal channels shorted together.
8) - This step bypasses the encoder and tests each encoder signal channel individually. Helps isolate between encoder and module malfunctions.
9) - This step tests the suspect encoder signal channel(s) for an open.
10) - This step tests the encoder signal channels for proper reference voltage.
11) - This step helps determine if the encoder signal ground circuit is shorted to voltage.
12) - This step tests the 8 volts reference circuit for a short to voltage.
13) - This step tests the encoder signal ground circuit for high resistance or an open.
14) - This step tests the 8 volts reference circuit for an open.
15) - This step repairs a shorted condition between the circuits that were simultaneously turned ON in Step 6.
16) - This step tests the encoder signal channel(s) that are not within the specified range previously tested in Step 9 for an open circuit.

Scheme 221

Scheme 222

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

2) - This step tests the 4WD low signal circuit for voltage.
3) - This step tests the 4WD low signal circuit for a short to voltage.
4) - This step tests the 4WD low signal circuit for an open or high resistance.
5) - This step repairs the 4WD low signal circuit for a short to voltage.

Scheme 223

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

2) - This step tests the operation of the front axle switch.
3) - This step tests the electrical control of the front axle switch.
4) - This step tests the axle actuator control circuit for a short to voltage.
5) - This step inspects for poor connections at the front axle actuator.
6) - This step inspects for poor connections at the harness connector, of the transfer case shift control module.

Scheme 224

The number below refers to the step number on the diagnostic table.

2) - This step replaces the transfer case shift control module.

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

3) - This step tests whether the condition is module, system or condition related.
4) - This step tests whether the condition has been corrected or identified as specified in the supporting text.
5) - This step replaces the transfer case shift control module.

Symptoms - Transfer Case

Important: Perform the Transfer Case Diagnostic System Check before using the Symptom Tables in order to verify that all of the following conditions are true

DTCs are not set.
The control modules can communicate via the serial data link.

Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description & Operation .

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

2) - This step tests the electrical function of the front axle actuator. This step helps determine between mechanical and electrical malfunctions.
3) - This step tests for proper power and ground at the front axle actuator.
4) - This step tests the operation of the axle actuator control circuit.
5) - This step helps determine if the transfer case shift control module is able to monitor the front axle switch.
6) - This step tests the axle switch signal circuit for an open or high resistance.
7) - This step measures the voltage between the ignition 3 voltage circuit and ground.
8) - This step tests the axle actuator control circuit for an open or high resistance.
9) - This step inspects the front axle for a mechanical malfunction.
10) -. This step tests for open fuse in the ignition 3 voltage circuit.

Scheme 225

Scheme 226

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

2) - This step tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.
3) - This step tests for proper power and ground at the front axle actuator.
4) - This step tests the operation of the axle actuator control circuit.
5) - This step tests the electrical function of the axle actuator control circuit.
6) - This step tests for proper ignition 3 voltage to the front axle actuator.
7) - This step tests for open fuse in the ignition 3 voltage circuit.
8) - This step tests the axle actuator control circuit for an open or high resistance.
9) - This step tests the axle switch signal circuit for an open or high resistance.
10) - This step helps determine if the front axle actuator has a mechanical malfunction.
11) - This step tests the axle switch signal circuit for a short to voltage.
12) - Inspect the front axle for a mechanical malfunction.

Scheme 227

Scheme 228

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

2) - This steps tests the functionality of the transfer case shift control switch buttons.
3) - This step tests the modules ability to operate the transfer case modes.

Scheme 229

The number below refers to the step number on the diagnostic table.

2) - This step determines whether the failure is the result of a faulty transfer case shift control module or the instrument cluster.

The number below refers to the step number on the diagnostic table.

2) - Determines whether the failure is the result of a faulty transfer case shift control module or the instrument cluster.

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

2) - This step tests the transfer case electrical control of the indicator circuits.
3) - This step helps determine a short to ground in the suspect indicator control circuits.
4) - This step tests the suspect indicator control circuits for a short to ground.
5) - Repair short to ground in the suspect indicator control circuit.

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

2) - This step determines the position of the front axle actuator.
3) - This step helps determine if the front axle will not engage.
4) - This step helps determine if the front axle will not disengage.

Scheme 230

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

2) - This step tests the transfer case electrical control of the indicator control circuits.
3) - This step helps determine module failures.
4) - This step tests the affected indicator control circuit for an open or high resistance.
5) - This step tests the ignition 1 voltage circuit for an open or short to ground.