P0079
Exhaust Valve Control Solenoid Circuit Low Bank 1
Variable valve timing / lift
Generic OBD-II
High
What it means
P0079 means the PCM detected a low-voltage (short-to-ground or open) condition in the exhaust valve control solenoid circuit on bank 1. This solenoid adjusts the variable valve system; a circuit fault leaves it stuck, causing rough running, reduced power, and higher emissions. The fault is electrical — solenoid, connector, or wiring — though low oil can also affect these oil-actuated solenoids.
High
Can I keep driving? Usually yes, with reduced performance — a valve-control circuit fault causes rough running and lost power but won't normally strand you.
Common symptoms
What you'll notice
- Check-engine light on
- Rough or unstable idle
- Reduced power and poorer fuel economy
- Higher emissions
Common causes
Most likely first
- Short-to-ground or open (low-voltage fault) in the exhaust valve control solenoid circuit, bank 1Likely
- Failed exhaust valve control solenoidCommon
- Damaged or corroded wiring / loose connectorCommon
- Low or dirty engine oil affecting the oil-actuated solenoidLess often
- PCM control-circuit driver faultLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to confirm the operating conditions.
- Inspect the bank 1 solenoid connector and wiring for shorts-to-ground or opens.
- Check engine oil level and condition, since these solenoids are oil-actuated.
- Measure the solenoid resistance against spec and command it with a scan tool.
- Replace the solenoid if faulty; suspect the PCM only after wiring is verified good.
FAQ
Quick answers
Is it safe to drive with P0079?+
Short-term, usually yes, though with reduced performance and rough running. Repair it before valve control drifts further.
Can I just clear P0079?+
It returns until the low-voltage circuit fault or the solenoid is repaired.
Related codes
Often seen with P0079
Read & clear P0079 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX