B1790 – OBD-II DTC

OBD-II DTC B1790 – Autolamp Sensor Input Circuit Failure

DTC B1790 meaning

DTC B1790 refers to a fault in the Autolamp Sensor Input Circuit. This diagnostic trouble code indicates that the vehicle’s onboard diagnostic system has detected an issue with the sensor responsible for detecting ambient light levels, which is crucial for automatic headlight operation.

DTC B1790 symptoms

Common symptoms associated with DTC B1790 may include:

• Headlights not turning on or off automatically
• Dashboard warning lights illuminated
• Inconsistent operation of the vehicle’s lighting system
• Manual control of headlights required

DTC B1790 causes

Several factors can lead to the triggering of DTC B1790, including:

• Faulty autolamp sensor
• Wiring issues, such as shorts or open circuits
• Corroded or loose electrical connections
• Faulty body control module (BCM)

DTC B1790 seriousness

The seriousness of DTC B1790 can vary. While it may not pose an immediate safety risk, it can lead to visibility issues during nighttime driving or adverse weather conditions. It is advisable to address this code promptly to ensure proper vehicle lighting functionality.

How to diagnose DTC B1790

To diagnose DTC B1790, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the code.
2. Inspect the autolamp sensor and its wiring for visible damage.
3. Check electrical connections for corrosion or looseness.
4. Test the autolamp sensor with a multimeter to ensure it operates within specifications.
5. Examine the body control module for faults or software issues.

How to fix DTC B1790 step-by-step instructions

To fix DTC B1790, follow these steps:

1. Repair or replace any damaged wiring or connectors related to the autolamp sensor.
2. Replace the autolamp sensor if it is found to be faulty.
3. Reprogram or replace the body control module if necessary.
4. Clear the DTC using an OBD-II scanner.
5. Test the system to ensure proper operation of the autolamp feature.

How to erase DTC B1790

To erase DTC B1790, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Access the trouble codes menu on the scanner.
3. Select the option to clear or erase codes.
4. Confirm the action and wait for the scanner to complete the process.
5. Disconnect the scanner and perform a test drive to ensure the code does not return.

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