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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Blazer - 4WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 236 (Two Speed Automatic) 🢒 DTC C0327 Encoder Circuit Malfunction

Object Number: 564263 Size: MF
Transfer Case Control Components
Transfer Case Control Schematics

Circuit Description

The transfer Case Encoder is a switch that converts a shaft position, representing a mode or range position, into electrical signals for use by the transfer case shift control module. The encoder houses 4 Hall effect sensors that are used for channels P, A, B, and C. These sensors provide a path to ground, when a magnet, (part of the Motor Encoder), passes over them.

The transfer case shift control module supplies an 8 V reference and a ground circuit for the encoder Hall effect sensors to function.

The transfer case shift control module supplies current limited 5 V on all the channels, thus as these channels are pulled to ground, the module can interpret the location of the transfer case shift position.

This DTC detects an open, short to ground, or a short to voltage (12 V) in the encoder feed circuit, an open in the signal ground circuit, an open, short to ground, or short to voltage (12 V) in the Encoder channel circuits.

Conditions for Setting the DTC

The transfer case shift control module reads back all high or low voltage on the Encoder channel circuits.

Action Taken When the DTC Sets
    • All motor activity will stop and the Transfer Case Lock engaged.
    • A default rail to rail shift may be allowed, (toggle between 4H and 2H).
    • The SERVICE indicator (4WD/AWD) lamp will be latched on 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 no longer exists.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History DTCs can be cleared using a scan tool.

Test Description

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

  1. Tests the operation of the system.

    2.

  2. Helps determine if the encoder has supply voltage.

    3.

  3. Tests the encoder channels for proper reference voltage.

    4.

  4. Tests the encoder channels for an open or a short to power.

    5.

  5. Measures the voltage from the Encoder Feed reference circuit to the Encoder Signal Ground circuit.

    6.

  6. Tests for two or more encoder channels shorted together.

    7.

  7. Bypasses the encoder and tests each encoder channel individually. Helps isolate between encoder and module malfunctions.

    8.

  8. Tests the suspect encoder channel(s) for an open.

    9.

  9. Tests the encoder channels for proper reference voltage.

    10.

  10. Helps determine if the circuit is shorted to voltage.

    11.

  11. Tests the Encoder Feed circuit for a short to voltage.

    12.

  12. Tests the Encoder Signal Ground circuit for high resistance or an open.

    13.

  13. Tests the Encoder Feed circuit for an open.

    14.

  14. Repairs shorted condition between the circuits that were simultaneously turned ON in Step 6.

    15.

  15. Tests the encoder channel(s) that are not within the specified range previously tested in Step 9 for an open circuit.

DTC C0327 Encoder Circuit Malfunction

Step

Action

Value(s)

Yes

No

1

Was the Transfer Case Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

Important:: NEUTRAL range will only be obtained by pressing and holding both the 2 HI and 4 LO buttons simultaneously for 10 seconds. Refer to Circuit Description.

  1. Install a scan tool.
  2. Start the engine.
  3. Place transmission into NEUTRAL (or clutch pedal depressed on manual transmission applications).
  4. Set the park brake.
  5. Observe Commanded Mode Indicator state on the scan tool while depressing each of the Mode/Range buttons.

Does the state change with the press of any of the Mode/Range buttons?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the encoder motor pigtail connector.
  2. Turn the ignition ON, with the engine OFF.
  3. With the scan tool observe the states of the Encoder Circuit P, A, B, C.

Do all the circuits display OFF?

--

Go to Step 6

Go to Step 4

4

  1. With the encoder motor still disconnected turn the ignition ON, with the engine OFF.
  2. Measure the voltage between the transfer case encoder circuit channels P, A, B, and C to the Encoder Signal Ground circuit.

Is the voltage reading within the specified values?

4.8-5.1 V

Go to Step 17

Go to Step 5

5

Test the suspect circuit(s) for an open or a short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 18

6

  1. Disconnect the encoder.
  2. Turn the ignition ON, with the engine OFF.
  3. Measure the voltage from the Encoder Feed circuit to the Encoder Siganal Ground circuit.

Is the voltage reading within the specified values?

7-9 V

Go to Step 7

Go to Step 11

7

  1. With the scan tool observe the states of the Encoder Circuit P, A, B, C.
  2. Individually jumper the transfer case encoder circuits for channels P, A, B, and C to the Encoder Ground circuit.

Does more than one Encoder channels display ON simultaneously?

--

Go to Step 15

Go to Step 8

8

Do each of the circuits display ON when their individual circuit is jumpered to the Encoder Signal Ground circuit?

--

Go to Step 10

Go to Step 9

9

  1. Identify which Encoder Circuit(s) stays OFF.
  2. Disconnect the transfer case shift control module.
  3. Test the suspect circuit(s) for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 18

10

Measure the voltage between the transfer case encoder circuit channels P, A, B, and C to the Encoder Signal Ground circuit (the harness side at the transfer case).

Is the voltage reading within the specified values?

4.8-5.1 V

Go to Step 17

Go to Step 16

11

Was the voltage reading measured in Step 6 greater than the specified value?

9 V

Go to Step 12

Go to Step 13

12

  1. Disconnect the transfer case shift control module.
  2. Turn the ignition ON, with the engine OFF.
  3. Test the Encoder Feed circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 18

13

Test the Encoder Signal Ground circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 14

14

  1. Turn the ignition OFF.
  2. Disconnect the transfer case shift control module.
  3. Test the Encoder Feed circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 18

15

Repair the shorted condition between the circuits that were simultaneously turned ON in Step 7. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 19

--

16

Test the encoder channel(s) that are not within the specified range previously tested in Step 10 for an open circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 19

Go to Step 18

17

Replace the encoder motor. Refer to Motor/Encoder Replacement .

Is the replacement complete?

--

Go to Step 19

--

18

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

Is the replacement complete?

--

Go to Step 19

--

19
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK