C1790 – OBD-II DTC

OBD-II DTC C1790 – Air Suspension LR Air Spring/Shock Solenoid Output Circuit Failure

DTC C1790 meaning

DTC C1790 refers to a fault in the air suspension system, specifically indicating an issue with the left rear (LR) air spring or shock solenoid output circuit. This diagnostic trouble code (DTC) is triggered when the vehicle’s onboard diagnostic system detects a malfunction in the electrical circuit that controls the air spring or shock absorber on the left rear side of the vehicle. The air suspension system is responsible for maintaining ride height and comfort by adjusting the air pressure in the springs based on load and driving conditions.

DTC C1790 symptoms

Common symptoms associated with DTC C1790 may include:

• Warning lights on the dashboard, such as the air suspension warning light.
• Uneven ride height, with the left rear corner of the vehicle sitting lower than the others.
• Stiff or bouncy ride quality due to improper suspension function.
• Increased noise from the suspension system.
• Possible air leaks from the left rear air spring or shock.

DTC C1790 causes

Several factors can lead to the triggering of DTC C1790, including:

• Faulty left rear air spring or shock absorber solenoid.
• Wiring issues, such as damaged or corroded wires in the solenoid output circuit.
• Poor electrical connections, including loose or oxidized connectors.
• Faulty air suspension control module.
• Air leaks in the left rear air spring or associated components.

DTC C1790 seriousness

DTC C1790 is considered a moderate to serious issue, as it directly affects the vehicle’s suspension system. If left unaddressed, it can lead to:

• Decreased ride quality and comfort.
• Increased wear on suspension components.
• Potential safety hazards due to compromised handling and stability.
• Further damage to the air suspension system, leading to more costly repairs.

How to diagnose DTC C1790

To diagnose DTC C1790, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC C1790.
2. Inspect the left rear air spring and shock for visible damage or leaks.
3. Check the wiring and connectors in the solenoid output circuit for signs of wear or corrosion.
4. Test the solenoid operation using a multimeter to ensure it is receiving the correct voltage and is functioning properly.
5. Examine the air suspension control module for faults or error codes.
6. Perform a visual inspection of the entire air suspension system for any other potential issues.

How to fix DTC C1790 step-by-step instructions

To fix DTC C1790, follow these step-by-step instructions:

1. Clear the DTC using an OBD-II scanner.
2. Inspect and repair any damaged wiring or connectors in the left rear air spring/shock solenoid circuit.
3. If the solenoid is faulty, replace it with a new one.
4. Repair or replace the left rear air spring if leaks or damage are found.
5. Check the air suspension control module for proper operation and replace if necessary.
6. Recheck the system for any remaining issues and ensure all components are functioning correctly.
7. Clear the DTC again and take the vehicle for a test drive to confirm the issue is resolved.

How to erase DTC C1790

To erase DTC C1790, 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 scanner’s menu and select the option to read or clear trouble codes.
4. Choose to erase the DTCs, including C1790.
5. Confirm the action and wait for the scanner to complete the process.
6. Disconnect the scanner and start the vehicle to ensure the code does not reappear.

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