B1694 – Autolamp On Circuit Open

The ODBII code B1694 indicates that there is an open circuit in the autolamp on circuit, meaning the system is not receiving the expected signal to activate the autolamps.

The severity of ODBII code B1694 Autolamp On Circuit Open is generally considered moderate.

Common Causes For: B1693 Autolamp On Circuit Failure

• Open circuit in the autolamp wiring
• Faulty autolamp sensor
• Damaged or corroded connectors
• Faulty body control module (BCM)
• Blown fuse related to the autolamp system
• Short circuit in the wiring harness

Common misdiagnosis for B1694 Autolamp On Circuit Open

• Faulty headlight switch
• Defective body control module (BCM)
• Wiring issues or shorts in the circuit
• Malfunctioning relay
• Incorrectly diagnosed battery or charging system problems
• Issues with the autolamp sensor
• Faulty ground connections

Common Troubleshooting Steps

The OBD-II code B1694 refers to a problem with the autolamp (automatic headlight) system, specifically indicating that there is an open circuit in the autolamp on circuit. Here are some common troubleshooting steps to diagnose and potentially resolve this issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information about the autolamp system and wiring diagrams.
• Visual Inspection:
• Inspect the wiring and connectors associated with the autolamp system for any signs of damage, corrosion, or loose connections.
• Check the headlight switch and any related components for physical damage.
• Test the Autolamp Relay:
• Locate the autolamp relay in the fuse box and test it for proper operation. You can swap it with a similar relay to see if the issue persists.
• Check Fuses:
• Inspect the fuses related to the autolamp system. Replace any blown fuses and check if the code returns.
• Measure Voltage and Ground:
• Use a multimeter to check for voltage at the autolamp circuit. Ensure that the circuit is receiving the correct voltage when the autolamp is supposed to be activated.
• Check for a good ground connection in the circuit.
• Inspect the Headlight Switch:
• Test the headlight switch for proper operation. If the switch is faulty, it may not send the correct signal to the autolamp circuit.
• Scan for Additional Codes:
• Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Check for Short Circuits:
• Inspect the wiring for any short circuits that could affect the autolamp circuit. This includes checking for damaged insulation or pinched wires.
• Test the Autolamp Sensor:
• If your vehicle is equipped with a light sensor, test it to ensure it is functioning correctly. A faulty sensor may not trigger the autolamp system.
• Clear the Code and Test Drive:
• After performing the necessary repairs, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns. 1
• Consult a Professional:
• If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1694 code.