2010 Cadillac CTS Sedan AWD V6-3.6L Page 508
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the high beam relay.
2. Connect a test lamp between the control circuit terminal 86 and the B+ circuit terminal 85.
3. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded
states.
瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the
BCM.
4. If all circuits test normal, replace the high beam relay.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Underhood Electrical Center or Junction Block Replacement (See: Maintenance/Fuses and Circuit Breakers/Fuse Block/Service and
Repair/Removal and Replacement/Underhood Electrical Center or Junction Block Replacement)
* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay
Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming
B2585
DTC B2585
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 Descriptor
DTC B2585 00
- Park Lamp Control Circuit
Diagnostic Fault Information
Circuit/System Description
Battery positive voltage is applied at all times to both the coil and switch sides of the LT/POS/LP relay located in the rear fuse block. The turn
signal/multifunction switch is suppled with ground at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground
is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control
