Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC U1500 00: LIN Bus FaultDTC U1511 00: Lost Communication With RCM
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Linear Interconnect Network Bus | U1500, U1511 | U1511 | U1500, U1511 | -- |
Battery Positive Voltage | U1511 | U1511 | -- | -- |
Ground (rear window motor) | -- | U1511 | -- | -- |
Circuit/System Description
The remote compass module (RCM) communicates with the body control module (BCM) utilizing a single wire LIN communication link. The BCM is the gateway for the GMLAN network. All data is communicated on the LIN bus, therefore there are only 3 circuits to the module as follows:
| • | Ground |
| • | LIN bus |
| • | Voltage |
Conditions for Running the DTC
The system voltage is between 9-16 volts.
Conditions for Setting the DTC
| • | The local interconnect network bus circuit has an open/high resistance, short to ground, or a short to voltage. |
| • | The ignition voltage circuit of the RCM is open or shorted to ground. |
| • | The ground circuit of the RCM is open. |
Action Taken When the DTC Sets
RCM will not operate
Conditions for Clearing the DTC
| • | The current DTC will clear when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Verify that DTC B1433 is not set.
| ⇒ | If DTC is set, refer to DTC B1433 . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the RCM.
- Test for less than 2.0 ohms between the ground circuit terminal 2 and ground.
- Ignition ON, engine running, verify a test lamp illuminates between the ignition voltage circuit terminal 1 and ground.
- Test for 5.5-7.0 volts between the LIN circuit terminal 3 and ground.
- Ignition OFF, disconnect the harness connector X5 at the BCM.
- Ignition OFF, test for less than 5.0 ohms between the run relay coil control circuit terminal 13 and ground.
- If all circuits test normal, replace the RCM.
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal and the RCM fuse is open, replace the RCM |
| ⇒ | If greater than the specified range, test the LIN circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified range, test the LIN circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for BCM and RCM replacement, setup, and programming
