C1791 – OBD-II DTC

OBD-II DTC C1791 – Air Suspension LR Air Spring/Shock Solenoid Output Circuit Open

DTC C1791 meaning

DTC C1791 refers to an issue with the air suspension system, specifically indicating that there is an open circuit in the left rear air spring or shock solenoid output circuit. This code is part of the On-Board Diagnostics II (OBD-II) system, which monitors various vehicle components to ensure proper functionality. When the system detects that the solenoid output circuit is open, it triggers this diagnostic trouble code (DTC) to alert the technician of a potential problem.

DTC C1791 symptoms

Common symptoms associated with DTC C1791 may include:

• Warning light illuminated on the dashboard
• Uneven ride height or sagging on the left rear side
• Increased noise from the air suspension system
• Loss of air suspension functionality
• Vehicle stability issues during driving

DTC C1791 causes

Several factors can lead to the triggering of DTC C1791, including:

• Faulty left rear air spring or shock solenoid
• Damaged wiring or connectors in the solenoid output circuit
• Corrosion or poor connections at the electrical terminals
• Malfunctioning air suspension control module
• Air leaks in the suspension system

DTC C1791 seriousness

The seriousness of DTC C1791 can vary depending on the symptoms and the vehicle’s intended use. It is generally considered a moderate to high priority issue because:

• It can affect vehicle handling and stability.
• It may lead to further damage to the air suspension system if not addressed.
• It can compromise passenger comfort and safety.

How to diagnose DTC C1791

To diagnose DTC C1791, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC C1791.
2. Inspect the left rear air spring and shock solenoid for visible damage.
3. Check the wiring and connectors for signs of wear, corrosion, or disconnection.
4. Test the solenoid with a multimeter to ensure it is functioning correctly.
5. Examine the air suspension control module for faults or error codes.
6. Perform a continuity test on the solenoid output circuit.

How to fix DTC C1791 step-by-step instructions

To fix DTC C1791, follow these step-by-step instructions:

1. Address any visible damage to the left rear air spring or shock solenoid by replacing it if necessary.
2. Repair or replace any damaged wiring or connectors in the solenoid output circuit.
3. Clean any corroded terminals and ensure all connections are secure.
4. If the solenoid is faulty, replace it with a new one.
5. Reset the air suspension control module if applicable.
6. Clear the DTC using an OBD-II scanner and perform a test drive to ensure the issue is resolved.

How to erase DTC C1791

To erase DTC C1791, 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. Access the DTC menu on the scanner and locate DTC C1791.
4. Select the option to clear or erase the trouble code.
5. Turn off the ignition and disconnect the scanner.
6. Start the vehicle and monitor for any reoccurrence of the code.

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