Faulty steering angle sensor or its wiring, providing incorrect data to the control module; Variable effort steering solenoid failure or contamination, preventing proper hydraulic pressure modulation; Damaged or corroded electrical connectors at the steering rack or control module; Low power steering fluid level or a leak affecting system pressure and sensor readings; A failing power steering control module or body control module that manages the variable assist function; Wiring harness damage from road debris, heat, or chafing, causing intermittent open or short circuits

DTC codes / C00xx · Brakes, steering and suspension / C0079

C0079Variable Effort Steering

Q: What does code C0079 mean?

Variable Effort Steering. C0079 indicates a fault in the variable effort steering system, which adjusts steering assist based on vehicle speed and driving conditions to improve feel and stability. The electronic control module has detected an electrical or performance issue within the system, such as an out-of-range signal from the steering angle sensor or a problem with the variable effort solenoid, and has set this code to alert the driver.

C0079 indicates a fault in the variable effort steering system, which adjusts steering assist based on vehicle speed and driving conditions to improve feel and stability. The electronic control module has detected an electrical or performance issue within the system, such as an out-of-range signal from the steering angle sensor or a problem with the variable effort solenoid, and has set this code to alert the driver.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaBrakes, steering and suspension

Symptoms you may notice

Steering feels heavier or lighter than usual, especially at low or high speeds
The steering wheel may exhibit uneven effort or a sudden change in assist during turns
A stability control or traction control warning light may illuminate alongside the steering warning
The vehicle may default to a fixed steering assist mode, reducing driver confidence
Often no symptoms besides the warning light, with the system operating in a failsafe mode

Common causes, most likely first

Faulty steering angle sensor or its wiring, providing incorrect data to the control module
Variable effort steering solenoid failure or contamination, preventing proper hydraulic pressure modulation
Damaged or corroded electrical connectors at the steering rack or control module
Low power steering fluid level or a leak affecting system pressure and sensor readings
A failing power steering control module or body control module that manages the variable assist function
Wiring harness damage from road debris, heat, or chafing, causing intermittent open or short circuits

How to diagnose and fix it

Check power steering fluid level and condition, topping off or flushing if contaminated
Inspect all electrical connectors and wiring at the steering rack, sensors, and control module for corrosion or damage
Use a scan tool to read live data from the steering angle sensor and variable effort solenoid, comparing to specifications
Perform a visual inspection of the steering system for leaks, loose components, or obvious mechanical faults
Test the variable effort solenoid for resistance and function, replacing if out of specification
Check for technical service bulletins or software updates for the power steering control module
If all else fails, diagnose the control module with a factory-level scan tool and consider replacement after confirming power and ground integrity

Before you replace the steering rack

A low battery or charging system fault can cause voltage drops that trigger C0079, so always verify battery health and charging voltage first.
The steering angle sensor often requires recalibration after replacement or battery disconnect, and a misaligned sensor can set this code even when new.
Aftermarket electronic accessories or poor ground connections can introduce electrical noise that interferes with the variable effort steering signal.
Some vehicles use the same code for a performance fault in the variable effort solenoid circuit, not just a sensor issue, so follow the factory diagnostic flow.
A sticking or contaminated power steering control valve can mimic solenoid failure, so pressure testing the hydraulic circuit is a smart step before parts replacement.

Can I keep driving with C0079?

You can generally drive the vehicle, but expect reduced or inconsistent steering assist, which may make low-speed maneuvers harder and high-speed steering less stable. Avoid aggressive driving and have the system inspected promptly to prevent further damage or loss of assist.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.