Circuit Description
The front transfer case propshaft speed sensor generates the Front Propshaft Speed as shown by the scan tool. The rear transfer case propshaft speed sensor generates the Rear Propshaft Speed as shown by the scan tool. The front and rear transfer case propshaft speed sensors are Permanent Magnet (PM) generators. The PM generator produces a pulsing AC voltage. The AC voltage level and number of pulses increases as speed increases. The transfer case shift control module converts the pulsating AC voltage to a Propshaft Speed in rpm to be used for calculations. The Front Propshaft Speed and the Rear Propshaft Speed can be displayed with a scan tool.
This DTC detects greater than 20 percent difference in the speed sensor inputs.
Conditions for Setting the DTC
The transfer case shift control module detects continued readings of Front and Rear Propshaft Speed signals which do not match. The module cannot determine propshaft speed.
The system will log the DTC if the Front and Rear Propshaft Speed inputs indicates a speed of greater than 20 percent difference for 40 seconds while all of the following are true:
| • | Transmission NOT in PARK or NEUTRAL |
| • | Engine is running |
| • | Front Propshaft Speed indicates speed less than 75 MPH |
| • | Front Propshaft or Rear Propshaft Speed exceeds 512 RPM |
| • | VCM monitored Vehicle Speed on Class 2 Data bus exceeds 10 MPH |
Action Taken When the DTC Sets
The system will not allow any further adaptive events (correct slip). The SERVICE indicator (AWD/4WD) lamp will be latched on for the remainder of the current ignition cycle
Conditions for Clearing the DTC
| • | Current DTC |
| The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exists. |
| • | History DTC |
| - | Once 100 consecutive ignition cycles without a fault present. |
| - | A scan tool CLEAR CODES command. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step attempt to determine whether a fault exists in the rear propshaft speed sensor circuit.
-
This step attemps to determine whether a fault exists in the front propshaft speed sensor circuit.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 |
Important: : If DTC C0300 is also present perform the diagnostic for DTC C0300 before continuing. Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |||||||
2 |
Inspect the connectors for proper connection and for loose terminals. Was a problem found? | -- | Go to Step 6 | Go to Step 3 | ||||||
3 |
Were there any DTCs found? | -- | Go to Step 4 | |||||||
Are the rpm values approximately equal at the same speeds? | -- | Go to Step 5 | Go to Step 7 | |||||||
Are the rpm values approximately equal at the same speeds? | -- | Go to Step 8 | Go to Step 9 | |||||||
6 | Repair/replace as necessary. Is the action complete? | -- | Go to Step 10 | -- | ||||||
7 | Replace the transfer case rear vehicle speed sensor. Refer to Speed Sensor Replacement . Are the repairs complete? | -- | Go to Step 10 | -- | ||||||
8 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Are the repairs complete? | -- | Go to Step 10 | -- | ||||||
9 | Inspect/replace the front transfer case vehicle speed sensor reluctor wheel for damage, misalignment, and slipping. Are the repairs complete? | -- | Go to Step 10 | -- | ||||||
10 |
Have all the ATC components been reconnected and properly mounted? | -- | Go to Step 11 | -- | ||||||
11 | Clear all ATC codes. Have all the ATC codes been cleared? | -- | -- |
