Circuit Description
The rear propshaft speed sensor generates the Rear Propshaft Speed as shown by the scan tool. The rear propshaft speed sensor is a permanent magnet (PM) generator. 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 from the rear propshaft speed sensor to a Rear Propshaft Speed in RPM to be used for calculations. The Rear Propshaft Speed can be displayed with a scan tool.
This DTC detects an open, short to ground, or faulty sensor.
Conditions for Setting the DTC
The system will log the DTC if the Rear Propshaft Speed input indicates a speed of less than 16 RPM for 30 seconds while all of the following are true:
| • | Transmission NOT in PARK or NEUTRAL |
| • | Engine is running |
| • | Front Propshaft Speed exceeds 512 RPM |
| • | Vehicle speed monitored by the transfer case shift control module via Class 2 from the VCM 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. |
| - | You issue a scan tool CLEAR CODES command. |
Diagnostic Aids
An intermittent problem may be caused by a poor connection, break in the wire insulation exposing the internal wire, or a wire that is broken inside the insulation.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step determines if the rear speed sensor is able to generate AC current and indicates that both the sensor and wiring to the transfer case shift control module is good.
-
This step measures the internal resistance of the rear speed sensor and whether or not it is within acceptable limits.
-
This step determines if CKT 2222 has a short to voltage.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
2 |
Were there any Powertrain DTCs found? | -- | Go to Powertrain OBD System Check | Go to Step 3 |
3 |
Are the rpm values approximately equal at the same speeds? | -- | Go to Step 22 | Go to Step 4 |
Does the voltage vary between the specified values? | 0-0.5 V | Go to Step 20 | Go to Step 5 | |
Is the resistance reading within the specified values? | 1300-2700 ohms | Go to Step 6 | Go to Step 21 | |
6 | Measure the resistance between transfer case shift control module connector C1 terminals F5 and F6. Is the resistance reading less than the specified value? | OL | Go to Step 15 | Go to Step 7 |
Is the voltage greater than the specified value? | 0 V | Go to Step 16 | Go to Step 8 | |
8 | Measure the resistance between transfer case shift control module connector C1 terminal F6 and ground. Is the resistance reading less than the specified value? | OL | Go to Step 17 | Go to Step 9 |
9 | Measure voltage between transfer case shift control module connector C1 terminal F5 to ground. Is the voltage greater than the specified value? | 0 V | Go to Step 18 | Go to Step 10 |
10 | Measure the resistance between transfer case shift control module connector C1 terminal F5 and ground. Is the resistance reading less than the specified value? | OL | Go to Step 19 | Go to Step 11 |
11 | Measure the resistance between transfer case shift control module connector C1 terminal F6 and transfer case rear speed sensor terminal B. Is the resistance reading within the specified values? | 0-2 ohms | Go to Step 13 | Go to Step 14 |
12 | Measure the resistance between transfer case shift control module connector C1 terminal F5 and transfer case rear speed sensor terminal A. Is the resistance reading within the specified values? | 0-2 ohms | Go to Step 22 | Go to Step 13 |
13 | Repair an open in CKT 2221 between the speed sensor and the transfer case shift control module. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
14 | Repair an open in CKT 2222 between the speed sensor and the transfer case shift control module. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
15 | Repair a short between CKT 2221 and CKT 2222. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 22 | -- |
16 | Repair a short to voltage condition in CKT 2222. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
17 | Repair a short to ground condition in CKT 2222. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
18 | Repair a short to voltage condition in CKT 2221. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
19 | Repair a short to ground condition in CKT 2221. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 22 | -- |
20 | Replace the transfer case shift control module. Refer to transfer case shift control module replacement. Refer to Transfer Case Shift Control Module Replacement . Is the repair completed? | -- | Go to Step 22 | -- |
21 | Replace the transfer case rear speed sensor. Refer to Speed Sensor Replacement Is the repair completed? | -- | Go to Step 22 | -- |
22 | Reconnect all ATC system components, ensure that all the components are properly mounted. Have all the ATC components been reconnected and properly mounted? | -- | Go to Step 23 | -- |
23 | Clear all the ATC DTCs. Are all the ATC DTCs cleared? | -- | -- |
