P0079–P0085 Exhaust Valve Control Solenoid Circuit Low Bank 1
The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0079 | Exhaust Valve Control Solenoid Circuit Low Bank 1 | Investigate soon |
P0085 | Exhaust Valve Control Solenoid Circuit Low Bank 2 | Investigate soon |
The definition
P0079: Exhaust Valve Control Solenoid Circuit Low Bank 1.
P0079 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Unplug the sensor. If the reading jumps to full scale, the wiring is fine and the sensor has failed low.
- Check the sensor's 5V supply and its earth before condemning the sensor itself.
What actually causes this on a VAG
A "low" reading on the exhaust valve control solenoid circuit for bank 1 - the ECU sees that circuit being pulled towards earth when it should not be. On VAG engines this normally means the oil control valve for the exhaust camshaft adjuster, and on engines with switchable valve lift acting on the exhaust camshaft it can mean a lift actuator instead, so confirm which component the ECU named - and confirm your engine has exhaust cam adjustment at all, because not every VAG engine does. The two realistic causes are a short to earth somewhere in the wiring or a solenoid that has broken down internally. The ECU will usually shut the output off to protect itself, so the exhaust camshaft stops adjusting.
Most likely causes, in order
- Wiring shorted to earth. The solenoid's lead runs across a hot engine and is clipped along the cylinder head or cam cover, where the sheath hardens with heat cycling and can eventually wear through onto bare metal. Follow the lead by hand and eye from the plug back into the loom, looking for flattened, glazed or melted sections, particularly at clips and where it crosses brackets or moves with the engine on its mounts.
- Solenoid shorted internally. Heat and age break down the coil until it effectively becomes a short to earth. Where the intake-side solenoid is the same part number, swapping them and clearing the memory tells you immediately whether the fault belongs to the component or the wiring.
- Contaminated connector. Oil weeping from a cam cover seal, or water and salt ingress, bridges the terminals to earth and often produces a fault that comes and goes with the weather or engine temperature. Unplug, inspect for oil in the housing and corroded terminals, and dry and clean it before condemning parts.
- Damage from a previous repair. Crimped joints, taped splices and rodent-damage repairs in this area are a common source of shorts once they get hot and move about. If anyone has been in the loom, unwrap and inspect that section.
Worth knowing: Before buying anything, unplug the solenoid, clear the fault memory and run the engine for a moment. If the code changes to an open circuit or "high" version, the loom is intact and the solenoid is the culprit. If it still logs "low" with the solenoid disconnected, the short is in the wiring and a new solenoid will change nothing - the repair is in the loom.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
$249 once. No subscription, unlimited cars. Windows 10/11.
See VAGPULSE — $249 Look up another codeSoftware downloads instantly · cable ships September 30 · cable guarantee — refund if it won't connect
Prefer to work on your phone? The VAGPULSE Android app is a free download and its demo mode runs against a sample car with no hardware at all, so you can see exactly what it reads before spending anything. Reading your car with it needs the VAGPULSE cable, which comes with the licence.
Common questions
What does P0079 mean?
P0079 means Exhaust Valve Control Solenoid Circuit Low Bank 1. The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
Can I drive with P0079?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.