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 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 circuit.
Conditions for Setting the DTC
The transfer case shift control module has a predefined range, 0.5-4.5 volts, in which the encoder feed back should stay within. The DTC sets if the encoder signal feed back falls out of this range.
Action Taken When the DTC Sets
| • | All motor activity stops and the transfer case lock engages. |
| • | 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 mechanical condition of the shift lever detent shaft connected to the motor. If this shaft has too much mechanical play this can cause an under voltage or over voltage from the encoder causing the DTC to set.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step checks for a voltage reading on the scan tool.
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This step tests the encoder circuit for a current malfunction.
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This step tests for an internal encoder malfunction which is present only in certain areas of the encoder sensor.
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This step tests for proper reference voltage at the encoder.
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This step tests the 5-volt reference circuit for proper voltage when the low reference circuit is used as a ground.
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This step tests the 5-volt reference encoder circuit for a short to voltage, short to ground, an open or high resistance.
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After determining if the reference voltage measured in Step 4 is correct, Step 6 reviews the reading originally measured in Step 3 to see if it is higher or lower than what is expected. This step helps determine whether the encoder signal circuit is being pulled high or low.
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This step tests the encoder signal circuit and the encoder low reference circuit for a short to voltage.
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This step helps determine a faulty encoder.
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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 - Transfer Case? | -- | 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 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 sensor. Refer to Encoder Motor Sensor Replacement . Did you complete the repair? | -- | Go to Step 15 | -- |
14 | 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 |
