C0079: Variable Effort Steering
What to do
The steering still works normally — it may just feel lighter or heavier than you are used to. If it feels over-light at motorway speed, allow for that and make smaller inputs. Not urgent, but worth diagnosing, particularly because the cause is often a wheel speed signal rather than the steering itself.
What this code means
The variable effort steering circuit has a fault.
Variable effort steering makes the wheel light when parking and heavy at speed, and it is on the braking module's list because it reads the same wheel speed sensors.
The two demands genuinely conflict. Manoeuvring wants as much assistance as possible; at motorway speed that same assistance makes the car twitchy and tiring, because a small movement of a very light wheel is a large change of direction. So the system varies the assistance with road speed.
A fault usually defaults to the safe end — full assistance, all the time. The car remains perfectly steerable; it simply feels vague and over-light at speed, which is a comfort and confidence problem rather than a safety failure. Some systems fail the other way and leave the steering heavy at parking speeds, which is more noticeable and more tiring.
Because it depends on a road speed signal, the fault is often not in the steering at all. A wheel speed sensor fault or a lost speed message will produce it. Check for other chassis codes before looking at the steering system.
Likely causes
Start here
- Corroded or loose connector · specialist
- Damaged wiring harness · specialist
- Failed power steering control module · specialist
Less common
- Faulty wheel speed sensor · specialist
- Faulty stability control module · specialist
Symptoms
Components involved
Information, not instruction
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Community experience
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