Circuit Description
This is a trouble code (both current and history) that indicates that the headlamps were not on when the Automatic Lighting Control (ALC) Relay output was ON.
Conditions for Setting the DTC
Meet all of the following conditions:
| • | The ALC headlamp relay output is active |
| • | The ALC option is enabled and ignition 1 is active |
| • | The high beams are either OFF or in DRL mode |
| • | The low beams are OFF for 5 seconds |
Action Taken When the DTC Sets
| • | Stores the DTC B2575 in the body control module (BCM) memory. |
| • | The SERVICE VEHICLE SOON indicator illuminates. |
| • | The check gauges chime sounds. |
Conditions for Clearing the DTC
| • | The BCM reads the proper headlamp voltage. |
| • | Conditions for the fault are no longer present. |
| • | All the BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles. |
| • | Use the Scan Tool . |
Diagnostic Aids
| • | Turn the ignition switch to the ON position, cover the ambient light sensor on the dash, and wait for 8 seconds. The low beams should illuminate. If the low beams do not illuminate, refer to Headlight: Daytime Running Lights, Cell 102, in Lighting Systems. |
| • | Turn the Ignition Switch to the ON position, activate the High Beams, and cover the Ambient Light Sensor on the dash then wait for 8 seconds. The High Beams should illuminate. If the High Beams do not illuminate refer to Headlight: Daytime Running Lights, Cell 102, in Lighting Systems. |
| • | If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while wiggling the wires and connectors; this can often cause the malfunction to appear. |
Test Description
The numbers below refer to the numbers on the diagnostic table.
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This step tests to see if the Body Control Module (BCM) is receiving the input which indicates that the low beam headlamps are working properly.
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This step determines if the underhood wiring harness junction block has a short to ground and whether the Body Control Module (BCM) is receiving the input which indicates that the low beam headlamps are working properly.
Step | Action | Value(s) | Yes | No | ||
|---|---|---|---|---|---|---|
|
Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open. | ||||||
1 | Was the Body Control Module (BCM) System Check performed? | -- | Go to Step 2 | Go to the Body Control Module System Check | ||
2 | Are any other Automatic Lighting Control (ALC) DTCs present? | -- | Correct other Automatic Lighting Control (ALC) DTCs first | Go to Step 3 | ||
3 | Turn the headlamp switch to the ON position, with low beams selected. Do both low beam headlamps light? | -- | Go to Step 4 | Go to Step 7 | ||
With a Scan Tool , read the BCM input for the LOW BEAM/DRL FEEDBACK. Is the BCM input for the LOW BEAM/DRL FEEDBACK reading LOW BEAM ON? | -- | Go to Step 5 | Go to Step 8 | |||
5 | Turn the headlamp switch to the ON position, with the high beam headlamps selected. Do the high beam headlamps light? | -- | Go to Step 6 | Go to Step 7 | ||
With a Scan Tool , read the BCM input for the HIGH BEAM FEEDBACK. Is the BCM input for the HIGH BEAM FEEDBACK reading HIGH BEAM ON? | -- | Go to Step 12 | Go to Step 10 | |||
7 | Repair the headlamps circuit. Refer to Headlights/Daytime Running Lights (DRL) Schematics . Is the repair complete? | -- | Go to Step 13 | -- | ||
8 |
Does the voltage at the terminal B4 equal the specified value? | B+ | Go to Step 12 | Go to Step 9 | ||
9 | Repair the open CKT 1201 (DK BLU) between the BCM and the underhood fuse block. Is the repair complete? | -- | Go to Step 13 | -- | ||
10 |
Does the voltage at the terminal A5 equal the specified value? | B+ | Go to Step 12 | Go to Step 11 | ||
11 | Repair the open in CKT 1200 (PNK) between the BCM and the underhood fuse block. Is the repair complete? | -- | Go to Step 13 | -- | ||
12 | Replace the BCM. Refer to the following procedures:
Is the repair complete? | -- | Go to Step 13 | -- | ||
13 | Clear the DTCs from the memory. Are the DTCs cleared from the memory? | -- | Go to the Body Control Module System Check | -- | ||
