P0079 Exhaust Valve Control Solenoid Circuit Low Bank 1

P0079 indicates a low exhaust valve control solenoid circuit on bank 1. The exhaust VVT control path is grounded or below expected voltage.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not reset adaptations or replace timing parts until the low exhaust solenoid circuit is repaired.

Symptoms of P0079

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0079

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Measure exhaust solenoid control voltage, feed, ground, resistance, and current draw while checking for short-to-ground faults.
Inspect connector terminals, oil contamination, harness routing near the cylinder head, fuse supply, and module driver output.
Compare low circuit behavior with commanded exhaust timing, actual cam angle, engine idle, and freeze-frame system voltage.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.