B1758 – Seat Driver Rear Down Circuit Open

The ODBII code B1758 indicates an open circuit in the driver rear seat down adjustment mechanism, meaning there is a fault preventing the seat from moving down properly.

The severity of ODBII code B1758 is moderate.

Common Causes For: B1757 Seat Driver Rear Down Circuit Failure

• Open circuit in the wiring
• Faulty seat motor
• Defective seat switch
• Poor ground connection
• Damaged connectors or terminals
• Faulty body control module (BCM)

Common misdiagnosis for B1758 Seat Driver Rear Down Circuit Open

• Faulty seat switch
• Wiring issues or shorts
• Defective seat motor
• Malfunctioning body control module (BCM)
• Poor ground connection
• Incorrectly installed or damaged seat harness
• Faulty connector or terminal corrosion

Common Troubleshooting Steps

The OBD-II code B1758 indicates a problem with the driver rear seat down circuit, specifically that the circuit is open. This can be related to the seat’s power adjustment system. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• Visual Inspection:
• Check the wiring harness and connectors associated with the driver rear seat. Look for any signs of damage, corrosion, or loose connections.
• Inspect the seat adjustment switch for any visible damage or wear.
• Check Fuses:
• Locate the fuse box and check for any blown fuses related to the seat adjustment system. Replace any blown fuses and see if the issue persists.
• Test the Seat Switch:
• Use a multimeter to test the seat adjustment switch for continuity. If the switch is faulty, it may need to be replaced.
• Inspect the Seat Motor:
• If the switch is functioning correctly, check the seat motor itself. Test the motor for proper operation by applying direct power to it (if safe to do so) to see if it moves.
• Check for Ground Issues:
• Ensure that the ground connections for the seat motor and switch are secure and free of corrosion. A poor ground can cause an open 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.
• Wiring Continuity Test:
• Perform a continuity test on the wiring between the seat switch and the seat motor. Look for any breaks or shorts in the wiring.
• Inspect the Body Control Module (BCM):
• If all other components check out, the issue may lie within the BCM. Check for any software updates or known issues with the BCM related to seat adjustments.
• Clear Codes and Test Drive:
• After performing repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Repair Manual:
• If the issue persists, consult the vehicle’s repair manual for specific diagnostic procedures related to the B1758 code. If you’re not comfortable performing these steps or if the issue remains unresolved, it may be best to consult a professional mechanic for further diagnosis and repair.