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 Descriptor
DTC B2575 00: Headlamp Low Beam Control CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Flash to Pass Switch Signal | 1 | 1 | 1 | -- |
Headlamp High Beam Relay Control | 1 | 1 | B2580 00, 1 | -- |
Headlamp Low Beam Relay Control | 1 | 1 | B2575 00, 1 | -- |
Headlamp Switch High Beam Signal | 1 | 1 | 1 | -- |
Headlamp Switch Headlamps ON Signal | B257A 00, 1 | 1 | 1 | -- |
Headlamp Switch Headlamps OFF Signal | B257A 00, 1 | 1 | 1 | -- |
LF High Beam Headlamp Voltage Supply | 1 | 1 | 1 | -- |
LF Low Beam Headlamp Voltage Supply | 1 | 1 | 1 | -- |
RF High Beam Headlamp Voltage Supply | 1 | 1 | 1 | -- |
RF Low Beam Headlamp Voltage Supply | 1 | 1 | 1 | -- |
LF Headlamp Ground | -- | 1 | -- | -- |
RF Headlamp Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 1 | -- | -- |
1. Headlamps Malfunction | ||||
Circuit/System Description
When the turn signal/multifunction switch is placed in the headlamp position, ground is applied to the body control module (BCM) through the headlamp low beam signal circuit. The BCM then applies ground to the headlamp low beam relay control circuit which energizes the low beam relay, applying battery voltage through the LOW BEAM fuses to the low beam headlamps. For more detailed information concerning headlamp operation refer to Exterior Lighting Systems Description and Operation .
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
DTC B2575 00 will set when the BCM detects a short to voltage in the headlamp low beam relay control circuit.
Actions Taken When the DTC Sets
When DTC B2575 00 is present, the low beam headlamps will not operate.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the low beam relay.
- Connect a test lamp between the low beam relay control circuit terminal R23 and the voltage supply circuit terminal R22.
- Command the low beam headlamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the low beam relay.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
