NVG 226-NP8 Transfer Case

DTC C0327

Circuit Description

The transfer case encoder is an analog sensor that returns a signal that represents the physical position of the transfer case sector shaft. This signal represents the mode, or range, position that the transfer case is currently in. This sensor is made up of the following 3 circuits.

- A 5 volt reference circuit.
- An encoder signal circuit.
- An encoder low reference circuit.

This DTC detects an out of range reading from the encoder signal, a short to voltage on the 5 volt reference, encoder circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0327 Encoder Circuit Malfunction.

Conditions for Setting the DTC

The transfer case shift control module has a predefined range in which the encoder feedback should stay within, which is 0.5-4.5 volts. The DTC sets if the encoder signal feedback falls out of this range.

Action Taken When the DTC Sets

- All motor activity will stop and the transfer case lock will engage.
- 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.

Diagnostic Aids

1. Check the encoder feedback voltage if the feedback voltage is above 4.5 volts then a clutch wear out condition is possible which may include apply plate or apply plate bearing damage. Tear down, inspect and repair as necessary. A clutch wear out condition may be accompanied by transfer case noise.
2. If the encoder voltage is below 0.5 volts then the condition is either high resistance in the wiring or a faulty encoder. A clutch wear out condition or apply plate damage in 4 low will cause the voltage to go below 0.5 volts.

Test Description

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

2. This step tests for a voltage reading on the scan tool.
3. This step tests the encoder circuit for a current malfunction.
4. This step tests for an internal encoder malfunction which is present only in certain areas of the encoder sensor.
5. This step tests for proper reference voltage at the encoder.
6. This step tests the 5-volt reference circuit for proper voltage when the low reference circuit is used as a ground.
8. This step tests the 5-volt reference encoder circuit for a short to voltage, short to ground, an open or high resistance.
9. After determining that the reference voltage measured in Step 4 was correct, Step 6 reviews the reading originally measured in Step 3 to see if it was higher or lower than what should have been expected. This step helps determine whether the encoder signal circuit is being pulled high or low.
10. This step tests the encoder signal circuit and the encoder low reference circuit for a short to voltage.
11. This step helps determine a faulty encoder.
12. This step tests the encoder signal circuit and the encoder low reference circuit for an open or a short to ground.