• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Headlamp High Beam Relay B+ | 1 | 1 | -- | -- |
Headlamp Low Beam Relay B+ | 1 | 1 | -- | -- |
Ambient Light Senor Signal | B2645 02 | B2645 05 | B2645 05 | -- |
Flash to Pass Switch Signal | 1 | 1 | 1 | -- |
DRL Relay Control | 2 | 2 | 2 | -- |
Headlamp High Beam Relay Control | B2580 06 | B2580 06 | B2580 01 | -- |
Headlamp Low Beam Relay Control | 1 | 1 | 1 | -- |
LF Low Beam Headlamp Control | 1 | 1 | 1 | -- |
RF Low Beam Headlamp Control | 1 | 1 | 1 | -- |
Ambient Light Senor Low Reference | -- | 2 | 2 | -- |
LF Headlamp Ground | -- | 1 | -- | -- |
RF Headlamp Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 1 | -- | -- |
1. Headlamps Malfunction 2. Daytime Running Lamps Malfunction |
When the turn signal/multifunction switch is placed in the headlamps high or flash to pass (FTP) position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass switch signal circuit. The BCM applies ground to the headlamp high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the HI BEAM fuses to the high beam headlamps. Ground for the left headlamp is supplied at G101 and the right headlamp receives ground at G102.
• | Battery voltage must be between 9-16 volts. |
• | Headlamps ON. |
The DTC will set when the BCM detects a short to voltage in the high beam relay control circuit.
The DTC will set when the BCM detects a short to ground or an open in the high beam relay control circuit.
• | When DTC B2580 01 is present, the high beam headlamps and flash to pass (FTP) will not operate. |
• | When DTC B2580 06 is present, the high beam headlamps will be ON at all times or will not operate. |
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Headlights/Daytime Running Lights (DRL) Schematics
Exterior Lighting Systems Description and Operation
Control Module References for scan tool information
⇒ | 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 an open/high resistance. If the circuit tests normal, replace the BCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |