C0079: Variable Effort Steering (Subfault)

What it means

This code identifies a fault associated with variable effort steering. The specific failure depends on the diagnostic subtype.

At a glance

• Usually lights the ABS or stability-control warning light

How it works

Variable-effort steering changes steering assistance according to conditions such as vehicle speed. C0079 identifies a fault in that system, but the subtype is needed to distinguish a steering-system failure from a problem in its signal or circuit.

Common causes

Most likely first.

1. VES system fault

Symptoms

• Steering warning light
• Steering assist may be reduced or unavailable

How to diagnose it

1. Read the C0079 subtype and freeze-frame data, and check for other steering, ABS, or stability-control codes.
2. With the vehicle parked, note whether steering effort is unusually heavy or inconsistent and check for a steering warning.
3. Inspect the variable-effort steering wiring and connectors for damage, looseness, corrosion, or signs of fluid contamination where applicable.
4. Check battery and charging-system condition because low supply voltage can disrupt steering-control electronics.
5. Use scan-tool data and the vehicle wiring information to check the relevant steering input and output, then test the identified circuit to the manufacturer's specification.

Common fixes

• Clean and secure a loose or corroded steering-system connector.
• Repair damaged wiring or a poor ground in the variable-effort steering circuit.
• Correct a confirmed power-supply fault.
• Replace a failed steering actuator or control module only after the circuit and subtype checks identify it.

Can I keep driving?

If steering assist is reduced, erratic, or unavailable, avoid driving in traffic and arrange service; steering may require much more effort, especially at low speed. If steering feels normal, drive cautiously and have the fault checked promptly.