Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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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.
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The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to symptoms for other concerns.
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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.
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Vehicle speed is provided to the transfer case shift control module via Class 2 and can effect the setting of DTC C0300. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.
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Perform diagnostics for DTC C0300 and C0305 first before addressing other DTCs. DTC C0300 and C0305 can be responsible for setting other DTCs.
Step | Action | Yes | No |
|---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | |
Does the scan tool communicate with the transfer case shift control module? | Go to Step 3 | ||
Select the transfer case shift control module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 4 | Go to Symptoms | |
Does the scan tool display any DTCs which begin with a "U"? | Go to Step 5 | ||
5 | Does the scan tool display DTC P0502 or P0503? | Go to Applicable Powertrain OBD Diagnostic System Check | Go to Step 6 |
6 | Does the scan tool display DTC C0300 or C0305? | Go to DTC C0300 Rear Speed Sensor Malfunction or DTC C0305 Front Speed Sensor Malfunction | Go to Diagnostic Trouble Codes |
