B1572 – OBD-II DTC

OBD-II DTC B1572 – Door Ajar LR Circuit Open

DTC B1572 meaning

DTC B1572 refers to a diagnostic trouble code indicating a “Door Ajar LR Circuit Open” issue. This code is generated when the vehicle’s onboard diagnostic system detects an open circuit in the left rear door ajar switch. The door ajar switch is responsible for signaling whether the door is closed or open, and an open circuit can prevent the system from receiving accurate information about the door’s status.

DTC B1572 symptoms

Common symptoms associated with DTC B1572 may include:

• Warning lights on the dashboard, such as the door ajar indicator.
• Inconsistent or incorrect door status readings.
• Interior lights remaining on when the vehicle is in motion.
• Chimes or alerts indicating that a door is ajar when it is closed.

DTC B1572 causes

Several factors can lead to the occurrence of DTC B1572, including:

• A faulty left rear door ajar switch.
• Wiring issues, such as frayed or broken wires in the door harness.
• Corrosion or poor connections at the switch or connector.
• Faulty body control module (BCM) that misinterprets the switch signal.

DTC B1572 seriousness

The seriousness of DTC B1572 can vary depending on the vehicle’s use and the specific symptoms present. While it may not pose an immediate safety risk, it can lead to:

• Increased battery drain due to interior lights staying on.
• Inconvenience from alerts and warnings.
• Potential for further electrical issues if left unaddressed.

How to diagnose DTC B1572

To diagnose DTC B1572, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the B1572 code.
2. Inspect the left rear door ajar switch for physical damage or wear.
3. Check the wiring and connectors for signs of corrosion or damage.
4. Test the continuity of the wiring between the switch and the BCM.
5. Perform a functional test of the door ajar switch to ensure it operates correctly.

How to fix DTC B1572 step-by-step instructions

To fix DTC B1572, follow these steps:

1. Repair or replace any damaged wiring or connectors found during diagnosis.
2. If the door ajar switch is faulty, replace it with a new one.
3. Ensure all connections are secure and free of corrosion.
4. Clear the DTC using an OBD-II scanner.
5. Test the system by opening and closing the left rear door to verify that the code does not return.

How to erase DTC B1572

To erase DTC B1572, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn the ignition key to the “On” position without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to ensure the code does not reappear.

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