OBD-II trouble code
P0662: Intake Manifold Tuning Valve Control Circuit High (Bank 1)
The Bank 1 tuning valve circuit is sitting high when the module commanded it low. More than any other member of this family, this is the code where the answer is often that something simply is not plugged in — and it turns up most after work that required the plenum to come off.
Quick facts
- System
- Powertrain
- Category
- Air Intake / Manifold Control
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $0 – $900
- DIY difficulty
- Intermediate DIY
What does P0662 mean?
On a ground-switched solenoid circuit, a high reading is the module's normal resting state. Battery voltage comes down the feed wire, sits across the coil, and appears at the control terminal until the module pulls that terminal to earth. So P0662 is not really "too much voltage" — it is the module noticing that when it tried to pull the circuit down, nothing happened, and the voltage stayed where it was.
The list of ways that occurs is short and unusually practical. The circuit never made it to the solenoid, because a connector is unplugged or unlatched. The feed is missing, so there is no path through the coil. The coil itself has failed open. There is a break in the control wire between the module and the valve. Or, less often, something is holding the circuit up — a short to battery voltage from an adjacent wire — so the module cannot pull it down even though everything else is intact.
What makes this code worth its own page rather than a footnote on the open-circuit version is where it comes from. P0662 shows up disproportionately after service work, and specifically after any job that required getting into the top of the engine: an intake manifold gasket replacement, spark plugs on a transverse V6, a supercharger or intercooler service, a fuel injector job, a valve cover reseal. The tuning valve connector is small, lives in an awkward spot, and is easy to leave hanging or half-latched when everything is being reassembled around it in a confined space. A vehicle that developed this code within a few days of any of that work should have its connector checked before a meter is picked up. Doing that first has saved more hours on this code than any test procedure.
The second thing to check before opening the harness is the feed side. On many engines the tuning valve shares a fused supply with other solenoids — evaporative purge, recirculation, variable valve timing. If that fuse has blown or the shared feed has corroded, every solenoid on it goes open at once and each sets its own circuit code. Reading the full code list before chasing this circuit alone is the difference between fixing one wire and replacing three healthy solenoids. Companion codes from unrelated valves are not a coincidence here; they are the diagnosis.
The driving consequences match the rest of the family. The valve is stuck in its de-energised position, so the manifold is locked into one configuration and one end of the rev range loses its tuning. The car drives, nothing is being damaged, and there is a modest cost in economy and in the shape of the power delivery.
Common causes
- Solenoid connector left unplugged or unlatched after recent work on the top of the engine
- Blown fuse on a supply shared with other intake or emissions solenoids
- Tuning valve solenoid coil failed open internally
- Break in the control wire between the module and the solenoid
- Corroded or backed-out terminal in the solenoid connector
- Short to battery voltage from an adjacent damaged wire, holding the circuit high
- Loss of the ignition-switched feed to the solenoid from a corroded splice or relay
- Damaged connector lock allowing the plug to vibrate loose over time
- Failed module driver unable to pull the circuit down
Symptoms
- Check engine light appearing within days of intake, spark plug or fuel system work
- A flat spot at one end of the rev range with the rest of the range feeling normal
- Companion circuit codes from other solenoids sharing the same fused feed
- Reduced fuel economy and slightly softer throttle response through the transition point
- No physical click or movement from the valve when it is commanded with a scan tool
- Symptoms that started immediately after a repair rather than developing gradually
- Occasional intermittent setting and clearing where a connector is latched but marginal
- No noticeable driveability change at all on some engines, with the code found at inspection
Diagnostic steps
- 1.Ask what work has been done recently. This code appears disproportionately after any job requiring the plenum, valve covers or injectors to come off, and an unlatched connector is the leading cause in those cases.
- 2.Physically inspect and reseat the solenoid connector before connecting any test equipment. Confirm the lock has engaged rather than assuming it has because the plug looks seated.
- 3.Read the complete code list. Circuit codes from other solenoids alongside this one point at a shared fused feed rather than at this circuit.
- 4.Check the fuse feeding the solenoid group, and check for voltage at the solenoid feed pin with the ignition on.
- 5.Measure the solenoid coil resistance against specification. An open coil is a straightforward confirmation that the valve rather than the wiring is at fault.
- 6.Check continuity of the control wire from the solenoid connector back to the module connector, with both ends disconnected.
- 7.Test for voltage on the control wire with the solenoid disconnected and the ignition on. Battery voltage present where the circuit should be open indicates a short to power rather than an open.
- 8.Command the valve with a scan tool while listening or feeling for it to operate. A solenoid that clicks when commanded after a connector reseat has already been fixed.
- 9.Inspect the connector seal and pins for corrosion if the vehicle has no recent service history, since water intrusion produces the same open without anyone having touched it.
Repair cost
$0 – $900
This is one of the few codes with a genuine chance of costing nothing. If the fault is an unlatched connector after recent work, reseating it is the entire repair, and a shop that caused it during its own job should not be charging for it. Beyond that, diagnosis alone is $90 to $160. A blown fuse and the corroded splice that caused it runs $90 to $300. Connector or terminal repair is $100 to $280. Replacing an open-circuit solenoid is $130 to $700 with the same access-driven spread that governs the rest of this family — cheap when the valve is mounted externally, several hundred more when the plenum has to come off first. Repairing a break or a short to power inside the harness is $150 to $600. Module replacement is the least likely outcome and should only follow a fully proven circuit.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with intake manifold runner control actuator replacement preselected. Adjust labor rate and vehicle category to fit your situation.
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.