U1512

DTC U1500, U1511, U1512, or U1513

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Fault

DTC U1511 00
- Lost Communication With RCM

Diagnostic Fault Information






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.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the remote compass module (RCM).
2. Test for less than 2.0 ohms between the ground circuit terminal 2 and ground.

• If greater than the specified range, test the circuit for an open/high resistance.

3. Ignition ON, engine running, verify a test lamp illuminates between the ignition voltage circuit terminal 1 and ground.

• 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

4. Test for 5.5-7.0 volts between the LIN circuit terminal 3 and ground.

• 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.

5. If all circuits test normal, replace the RCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair. Verification Tests