2010 Cadillac CTS Sedan AWD V6-3.0L Page 2044
* Electronic Compass Module Replacement (Sedan) (See: Instrument Panel, Gauges and Warning Indicators/Compass/Service and Repair
)Electronic Compass Module Replacement (Wagon) (See: Instrument Panel, Gauges and Warning Indicators/Compass/Service and Repair)
U1513
DTC U1500, U1511, U1512, or U1513
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC U1500 01
- Inter-Device Dedicated Bus 1 Short to Battery
DTC U1500 02
- Inter-Device Dedicated Bus 1 Short to Ground
DTC U1511 00
- Inter-device Dedicated Bus Lost Communication With Device 1
DTC U1512 00
- Inter-device Dedicated Bus Lost Communication With Device 2
Diagnostic Fault Information
Circuit/System Description
The driver door module (DDM) and the front passenger door module (FPDM) communicate with window regulator motors on the local
interconnect network bus 1 and the local interconnect network bus 2 circuits respectively. When the driver power window switch is activated to a
desired position, the DDM examines the request and checks for messages from other vehicle control modules prohibiting window movement. If no
prohibitive messages have been received, the DDM will send a LIN serial data message to the driver door window motor to move the window to
the desired position.
When the DDM receives a request to operate one of the right side passenger windows from the driver master control, a GMLAN serial data
message is sent to the PDM. The PDM examines the request and checks for messages from other vehicle control modules prohibiting the window
movement. If no prohibitive messages have been received, the PDM will send a LIN serial data message to the appropriate window motor to move
the window as requested.
The DDM and PDM supply their respective rear power window switches with a 12-volt reference and signal circuit. The rear power window
switches contain separate resistors for each switch position. When a rear power window switch is activated, the associated door control module
interprets the signal and checks for messages from other vehicle control modules prohibiting the window movement. If no prohibitive messages
have been received, the door control module sends a LIN serial data message to the appropriate power window motor commanding the requested
window position.
The driver information center (DIC) displays the compass based on serial data message from the BCM. The compass module communicates with
the body control module (BCM) through a bi-directional data circuit (LIN). The instrument panel cluster (IPC) receives compass information from
the BCM via the serial data circuit.
Conditions for Running the DTC
