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.
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 Aid
- 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.
- 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.
-
This step tests for a voltage reading on the scan tool.
-
This step tests the encoder circuit for a current malfunction.
-
This step tests for an internal encoder malfunction which is present only in certain areas of the encoder sensor.
-
This step tests for proper reference voltage at the encoder.
-
This step tests the 5-volt reference circuit for proper voltage when the low reference circuit is used as a ground.
-
This step tests the 5-volt reference encoder circuit for a short to voltage, short to ground, an open or high resistance.
-
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.
-
This step tests the encoder signal circuit and the encoder low reference circuit for a short to voltage.
-
This step helps determine a faulty encoder.
-
This step tests the encoder signal circuit and the encoder low reference circuit for an open or a short to ground.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Are the voltage parameters displayed? | -- | Go to Step 3 | Go to Step 5 | |
Does the voltage reading stay within the specified values? | 0.5-4.5 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
Does the voltage reading stay within the specified values at any position? | 0.5-4.5 V | Go to Step 13 | Go to Step 5 | |
Does the voltage measure within the specified values? | 4.8-5.2 V | Go to Step 6 | Go to Step 8 | |
Test the low reference circuit by using a DMM to measure voltage from the 5-volt reference circuit pin A to the low reference circuit pin C at the encoder pigtail on the module side of the harness. Does the voltage reading stay within the specified values? | 4.8-5.2 V | Go to Step 9 | Go to Step 7 | |
7 | Test the low reference circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Test the 5-volt reference encoder circuit for a short to voltage, short to ground, an open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | |
Was the voltage reading measured in Step 4 greater than 5.2 volts? | -- | Go to Step 10 | Go to Step 11 | |
Test the encoder signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | |
Is the encoder return voltage display within the specified values? | 4.8-5.2 V | Go to Step 13 | Go to Step 12 | |
Test the encoder signal circuit and the encoder low reference circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | |
13 | Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the repair? | -- | Go to Step 15 | -- |
14 |
Important: After transfer case shift control module replacement and reprogramming, ensure all doors are closed and the key is out of the ignition, then open and close the doors again and wait 2 minutes to avoid incomplete programming or setting false communication DTCs. Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement and Transfer Case Shift Control Module Reprogramming . Did you complete the repair? | -- | Go to Step 15 | -- |
15 |
Does the DTC set? | -- | Go to Step 2 | System OK |
