B2580
DTC B2580
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B2580 02
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High Beam Control Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The headlamp high beam relay is supplied with battery voltage at all times. The turn signal/multifunction switch signal circuit is grounded by pressing the turn signal/multifunction switch. The body control module (BCM) energizes the headlamp high beam relay by applying ground to the headlamp high beam relay control circuit. When the headlamp high beam relay is energized, the relay switch contacts close and battery voltage is applied through the high beam lamp fuses to the high beam lamp supply voltage circuit which illuminates the high beam lamps.
Conditions for Running the DTC
High beam lamps ON.
Conditions for Setting the DTC
The BCM detects a short to ground on the high beam control circuit.
Action Taken When the DTC Sets
The high beam lamps are always ON.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Exterior Lighting Systems Description and Operation Exterior Lighting Systems
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
Ignition ON, headlamps ON, turn the high beam headlamps ON and OFF by applying and releasing the turn signal/multifunction switch. The high beam headlamps should turn ON and OFF when changing between the selected states.
Circuit/System Testing
1. Ignition OFF, disconnect the KR48 headlamp high beam relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Verify that a test lamp illuminates between the B+ circuit terminal 87 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the appropriate E13 headlamp.
6. Test for less than 5 ohms between the ground circuit terminal 1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the E13 headlamp.
8. Connect a 10 A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the high beam headlamp is activated.
• If the high beam headlamp does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the E13 headlamp.
• If the high beam headlamp does not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the E13 headlamp.
9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
10. Turn the high beam headlamps ON and OFF using the S78 turn signal/multifunction switch. The test lamp should turn ON and OFF when changing between the selected states.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
11. If all circuits test normal, test or replace the KR48 headlamp high beam relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Headlamp Replacement Headlamp Replacement
* Headlamp Bulb Replacement (TT4 Low Beam) Headlamp Bulb Replacement (TT4 Low Beam)Headlamp Bulb Replacement (TT4 High Beam) Headlamp Bulb Replacement (TT4 High Beam)
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Control Module References Programming and Relearning for BCM, replacement, programming and setup