My meter says the wire has continuity. Why is the module still reporting an open?

Because you and the module are testing under completely different conditions. An ohmmeter pushes a few milliamps through the circuit. The solenoid needs something close to an amp. A conductor corroded down to a few remaining strands, or a terminal whose contact area has shrunk to a point, will carry milliamps perfectly and read near zero ohms — then collapse the moment real current is demanded, dropping the supply voltage across the damaged section so the solenoid never operates. Both observations are true within their own test. The way to settle it is to energise the circuit and measure voltage drop rather than resistance.

How do I do a voltage drop test on this circuit?

Command the solenoid on, ideally with a bidirectional scan tool, so real current is flowing. Then measure the voltage between battery positive and the solenoid's supply terminal, and between the solenoid's ground return and battery negative. On a healthy low-current circuit each of those should be a couple of tenths of a volt at most. A reading of a volt or more tells you the fault lies within the section you just measured across, and you narrow it by moving your probes progressively closer together along the path — connector by connector. It finds high-resistance faults that no resistance measurement will reveal.

I have this code plus several other unrelated codes. Where do I start?

With the grounds, before anything gets taken apart. The module measures every circuit against its own ground reference, so a corroded engine-to-body strap or a loose module ground point shifts that reference and produces out-of-range readings across circuits that have nothing in common. That looks like several simultaneous failures and is actually one connection. Cleaning and re-terminating a ground strap is inexpensive and sits upstream of every other test, so if a scatter of unrelated circuit codes is present, that is where the time is best spent first.

This car has had valve timing solenoid codes before, at other positions. Is that relevant?

It is, and it should change what you suspect. One solenoid failing is ordinary wear. Several failing over time at different positions, on different banks and different camshafts, is a pattern, and patterns point at the things those positions have in common rather than at the parts themselves — the shared supply feed, the shared ground, or the module driving all of them. Before fitting another solenoid to a car with that history, test the supply and grounds properly and look hard at the module's output behaviour, because a fourth replacement solenoid is unlikely to be the last.

OBD-II trouble code

P0086: Exhaust Valve Control Solenoid Circuit High (Bank 2)

An open circuit on the bank 2 exhaust valve control solenoid — the longest branch in the valve control group. A continuity check will pass on a conductor with three strands left; a voltage drop test under load will not, and that difference decides this diagnosis.

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: $60 – $950
DIY difficulty: Advanced DIY

What does P0086 mean?

P0086 sets when the module sees the bank 2 exhaust valve control solenoid circuit sitting high with no current passing through it. The circuit is incomplete.

There is a specific reason this code catches people out, and it is a measurement problem rather than a wiring one. An ohmmeter tests a circuit with a current of a few milliamps. A solenoid circuit carries something closer to an amp. A conductor that has corroded until only a handful of strands remain intact, or a terminal whose contact area has been reduced to a point, will happily pass a few milliamps and show near-zero resistance on a meter — and then collapse under a real load, dropping most of the supply voltage across the damaged section so that the solenoid never receives enough to operate. The module sees no current and logs an open. The technician sees good continuity and concludes the wiring is fine. Both are looking at the same circuit and both are correct within their own test conditions.

The fix for that is to test with the circuit energised and measure voltage drop rather than resistance. With the solenoid commanded on, measure the voltage between the supply terminal and battery positive, and between the ground path and battery negative. On a healthy low-current circuit those figures should be small — a few tenths of a volt at most across the whole path. A drop of a volt or more localises the fault to the section you have just measured across, and you can walk it down the circuit connector by connector. That approach finds high-resistance faults an ohmmeter cannot see.

This matters more here than at any of the other three solenoid positions because this is the longest branch. It leaves the module, crosses the engine to the far cylinder head, and terminates on the exhaust side — the segment with the most length, the most junctions and the most heat exposure. Resistance accumulates along that path, so the margin between a healthy circuit and one the module reads as open is smaller here than anywhere else in the group.

The second thing to consider before you commit to this one circuit is whether it is really the only one misbehaving. If P0086 is stored alongside a scattering of unrelated circuit codes from different systems, the common factor is more likely to be a shared power or ground than a coincidental cluster of failures. A corroded engine-to-body ground strap or a loose module ground shifts the reference against which the module makes all its measurements, and the result is out-of-range readings on circuits that have nothing else in common. Checking and cleaning grounds is quick and cheap, sits upstream of everything else, and should happen before any single circuit gets taken apart.

There is also a fleet-level pattern worth noting. This is the last of the six valve control solenoid positions in the P0075 to P0086 block. A vehicle that has logged several of them over its life, on different banks and different cams, is telling you something about the module or the shared supply rather than about six independently failed solenoids.

The vehicle drives normally with the exhaust phaser at rest, at a small cost in economy and emissions.

Common causes

Corroded conductor reduced to a few strands, which passes a resistance check but collapses under load
High-resistance terminal in one of the intermediate connectors along the long far-bank branch
Corroded engine-to-body ground strap or loose module ground shifting the module's reference
Open winding inside the exhaust valve control solenoid
Broken conductor inside insulation that looks undamaged from outside
Loss of the ignition-switched supply feed to the solenoid
Connector left unseated or a terminal backed out after exhaust or driveline work
Previous crimp repair that has corroded internally and now behaves as a high-resistance joint
Failed module output driver leaving the circuit permanently off

Symptoms

Check engine light on with P0086 stored
Vehicle drives essentially normally
Small fuel economy penalty and elevated oxides of nitrogen
Several unrelated circuit codes stored at the same time, suggesting a shared ground or supply
Bank 2 exhaust cam position frozen at its rest value on live data
Solenoid silent during a bidirectional actuation test
History of repeated valve control solenoid codes at different positions over the vehicle's life

Diagnostic steps

1.Read all stored codes first, because a spread of unrelated circuit faults points at a shared ground or supply rather than at this one solenoid.
2.Inspect and clean the engine-to-body ground strap and the module ground points before disassembling any single circuit.
3.Command the solenoid on and measure voltage drop along the circuit rather than measuring resistance with the circuit dead.
4.Measure the drop from battery positive to the solenoid supply terminal and from the ground return to battery negative; more than a few tenths of a volt across a section localises the fault to it.
5.Walk the voltage drop test down the branch connector by connector, since the far bank's exhaust run carries more junctions than any other in this group.
6.Confirm battery voltage is present at the supply terminal with the ignition on before condemning the control leg.
7.Measure the solenoid coil resistance and compare with the bank 1 exhaust solenoid rather than relying on a single book value.
8.Look for previous crimp repairs in the branch and treat them as suspect regardless of what a resistance check says.
9.Review the vehicle's code history — repeated solenoid codes at several positions point at the module or a shared feed rather than at multiple failed parts.
10.After repair, clear the code, run an actuation test and confirm bank 2 exhaust cam position responds on a warm drive.

Repair cost

$60 – $950

Cleaning and re-terminating a corroded ground strap is $60 to $180 and is the cheapest outcome available here, which is why it belongs at the start rather than the end of the process. Diagnosis is $90 to $180. An exhaust valve control solenoid is $35 to $240 in parts with 0.8 to 3.5 hours of labour at this position, so $250 to $950 fitted. Repairing a high-resistance section or a corroded junction in the far-bank branch is $180 to $450. The costly error specific to this code is passing the wiring on a resistance check, replacing an expensive-to-reach solenoid, and finding the code still stored because the real fault only appeared once current had to flow.

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DIY vs shop

This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.