The code says control circuit. Why would I check the power supply?

Because the module can only watch one end of the circuit. The solenoid coil has a supply feed on one side and a control leg back to the module on the other. If the feed is dead, no current flows, and the module reports exactly the same thing it would report if the control wire were broken. It has no way to tell the difference. So the code names the half it can see rather than the half that failed. Confirming battery voltage at the feed terminal with the ignition on takes about a minute and eliminates half the circuit before you spend money.

I have several unrelated circuit codes stored at once. Is that a coincidence?

It is almost never a coincidence, and it is the most useful clue you will get. Several small actuators and solenoids usually share one ignition-switched fuse or relay. When that supply dies, every device downstream of it stops working at the same instant and each one logs its own circuit fault. What looks like five simultaneous failures is one fuse. Pull up the wiring diagram, find the fuse that feeds this solenoid, and check whether the other codes trace back to the same place. If they do, you are fixing one thing, not five.

Can I diagnose this myself with a cheap multimeter?

This is the one code in the group where that is realistic. An open circuit is a static condition, so it does not need the engine running, warm, or under load to show itself. Disconnect the solenoid and the module connector, measure resistance end to end along the control wire, and measure the coil across its own two terminals. Both readings are taken with the ignition off and both give a clear answer. The short-circuit versions of this fault are much harder because they can hide until things are hot and moving.

This circuit had a low-circuit code a while ago and now it has this one. Are they connected?

Very likely, and the sequence tells you something worth acting on. A wire that has rubbed through its insulation and touched ground will draw far more current than the circuit was designed for, and it can heat up enough at the contact point to burn the conductor apart. When that happens the fault flips from low to high. If you repair only the break you have fixed the symptom of the earlier problem. Find the spot where the loom is rubbing, correct the routing and re-protect it, or the next break will be a couple of inches further along.

OBD-II trouble code

P0080: Exhaust Valve Control Solenoid Circuit High (Bank 1)

The bank 1 exhaust valve control solenoid circuit is reading high, which means current is not flowing. The break can sit on either side of the coil, and the supply side is the half most people never check because the code says nothing about it.

Medium severityPowertrainVariable Valve TimingDrivable short-term

Quick facts

System: Powertrain
Category: Variable Valve Timing
Severity: Medium severity
Drivable: Usually safe to drive short-term
Repair cost range: $25 – $600
DIY difficulty: Intermediate DIY

What does P0080 mean?

P0080 sets when the module sees the control terminal of the bank 1 exhaust valve control solenoid sitting near battery voltage when it expected to see current flowing through the coil. No current means the circuit is not complete somewhere between the fuse and the module.

Here is the part that decides how long this job takes. A solenoid coil sits between two halves of a circuit: a supply feed coming from an ignition-switched fuse or relay, and a control leg that runs back to the module. The module can only watch the control leg. If the feed disappears, the module still sees no current, still sees the terminal sitting high, and still logs the control circuit code. The code names the half it can see, not the half that failed. Roughly half the time this fault is in the supply, and that half never gets looked at by anyone who takes the code literally.

That gives you a cheap first test that has nothing to do with the solenoid. Back-probe the feed terminal with the ignition on and confirm battery voltage is present there. It takes a minute and it splits the job in two before anything is removed.

Better still, most vehicles feed several solenoids and small actuators from one ignition-switched fuse or relay. If the feed is dead, other devices on that same fuse are also dead, and they will usually have logged their own codes. So read the whole code set, then look at the wiring diagram for the fuse that serves this solenoid and ask whether the other codes stored are all children of that fuse. A group of unrelated circuit codes that all trace back to one supply is a single fuse or relay problem wearing several disguises, and it is fixed in one place for a few dollars.

The second thing worth knowing about P0080 is that it is the only member of the bank 1 exhaust valve control block that you can chase with the engine off and cold. A short comes and goes with heat, movement and load; an open is a static condition. Disconnect the module connector and the solenoid connector, put an ohmmeter across the two ends of the control wire, and the answer is in front of you with no engine running and no live circuit. That makes P0080 the most tractable of these codes for someone working at home with a basic meter.

There is a history question worth asking too. If this circuit previously logged a low code and now logs P0080, that progression is meaningful: a conductor that chafed through its insulation and shorted to ground will often carry enough current to burn itself open, at which point the fault flips from low to high. Repairing the break without finding and correcting the abrasion point that caused it leaves the repair to fail again a little further along the same wire.

The vehicle stays driveable. The exhaust phaser sits at its default rest position, which is where it spends most of its life anyway, so power and drivability are close to normal. What you lose is the emissions and economy benefit of exhaust phasing, and on a car facing a tailpipe test that matters more than the driving impression suggests.

Common causes

Open or broken conductor in the control wire between the module and the solenoid
Loss of the ignition-switched supply feed to the solenoid — a blown fuse or failed relay upstream
Corroded, spread or backed-out terminal in the solenoid connector interrupting continuity
Solenoid with an internally open winding
Previous short to ground on this circuit that burned the conductor open, leaving the original chafe point intact
Connector unlatched or not fully seated after unrelated engine work
Damaged or disconnected ground return at the module affecting its ability to complete the circuit
Failed low-side driver in the module leaving the output permanently off
Repair splice or butt connector that has corroded and lost continuity

Symptoms

Check engine light on with P0080 stored
No noticeable change in how the vehicle drives
Small loss of fuel economy at steady cruise
Elevated oxides of nitrogen at a tailpipe emissions test
Other unrelated circuit codes stored at the same time, all fed by one shared fuse
Exhaust camshaft position no longer moving from its rest value on live data
Solenoid does not click when commanded during a bidirectional actuation test

Diagnostic steps

1.Read all stored codes and note anything else that looks like a circuit fault, because a group of unrelated open-circuit codes usually means one dead supply rather than several dead parts.
2.Look up which fuse or relay feeds this solenoid, then check whether the other codes stored are all served by that same supply.
3.With the ignition on, back-probe the supply terminal at the solenoid connector and confirm battery voltage is present — this splits the circuit in half before anything is removed.
4.If the feed is missing, work upstream to the fuse and relay rather than touching the solenoid at all.
5.With the ignition off, disconnect both the solenoid and the module connector and measure resistance end to end along the control wire; an open is a static fault and will show up cold.
6.Measure the solenoid coil resistance across its own terminals and compare against the manufacturer's specification — an infinite reading condemns the solenoid.
7.Inspect both connectors for green corrosion, spread terminal tension and pins pushed back out of the housing, which read as an open without looking like one.
8.Ask what work has been done recently, since an unlatched connector after other engine service is a common and free fix.
9.If this circuit has previously logged a low code, find and repair the abrasion point as well as the break, because the short is what caused the open.
10.After repair, clear the code, run a bidirectional actuation test to confirm the solenoid clicks, then verify exhaust cam position responds on live data during a warm-up drive.

Repair cost

$25 – $600

The range is wide because the outcomes are genuinely far apart. A blown fuse or a corroded connector terminal is $25 to $120 including the time to find it, and checking the feed first is what makes that outcome reachable. Diagnosis alone runs $90 to $180. An exhaust valve control solenoid is $35 to $240 in parts with 0.4 to 2.5 hours of labour depending on access, so $140 to $560 fitted. Repairing an open in the harness is $120 to $320. A failed relay is $30 to $150. The expensive mistake here is buying a solenoid because the code says circuit, when the supply feeding that solenoid was never checked and the solenoid was fine all along.

Estimate your repair

Run the numbers for your vehicle

Open the Repair Cost Estimator with vvt solenoid replacement preselected. Adjust labor rate and vehicle category to fit your situation.

Estimate your repair cost

DIY vs shop

This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.