OBD-II trouble code
P22C6: Turbocharger Compressor Outlet Valve Control Circuit Low
An open circuit leaves this valve inert. A short to ground does the opposite — it holds it actuated. And on an engine that measures its intake air before the turbo, a valve stuck open is metered air being thrown away, which the fuel calculation never finds out about.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $90 – $800
- DIY difficulty
- Intermediate DIY
Browse every code in P2200–P22CA, or start from the full code library.
What does P22C6 mean?
The compressor outlet valve releases boosted air that has nowhere to go in the moment after the throttle closes. This code says the module found the control circuit for that valve sitting at or near ground potential when it should not have been — a short to ground in the wiring, a bridged connector, or a driver output that has failed on.
The distinction that matters is between a circuit that has lost its connection and a circuit that has gained one. Lose it and the valve is unpowered and does nothing; the fault only shows itself in the instant the valve was meant to act. Gain an unintended path to ground and, on the common arrangement where the module completes the circuit by switching the low side, the valve is energised continuously whether it has been commanded or not. The valve is not idle. It is stuck in whatever position it takes when powered, all the time.
What that costs you depends on which type of valve the engine has, and this is worth establishing before anything else because the two produce different complaints and different repairs.
A recirculating valve returns the released air to the compressor inlet. Held open, it creates a permanent loop: the compressor pushes air out, the air comes straight back round to where it started, and very little of it reaches the engine. The car feels flat and boost is low or absent. Where the vehicle controls boost electronically, the module will also work the wastegate control harder trying to reach a target it cannot meet, so an underboost or boost-performance code stored alongside this one is a consistent finding rather than a separate fault.
A venting valve releases the air to atmosphere instead, and on an engine whose air is metered by a mass airflow sensor mounted ahead of the turbocharger, that has a second consequence that catches people out. Every gram of air that passes the meter has already been counted, and the fuel calculation is built on that count. Air counted and then dumped overboard never reaches a cylinder, but the fuel for it is still delivered. The result is an engine running persistently rich: heavy fuel consumption, a smell of unburnt fuel, sooted plugs, and rich fuel trim codes that will survive every vacuum test anyone performs on them.
The third thing to check has nothing to do with the turbo. A conductor shorted to ground carries more current than its circuit was designed around, and where that circuit shares a fuse with anything else, the fuse is what gives way. If something else on the vehicle stopped working at the same time as this code appeared, the two are related and the shared fuse is the link.
As for where the short is, start with the mechanical possibilities, because they are the ones you can see. This valve sits on or beside the compressor housing, and its lead has to get there past clamp bands, brackets, lifting eyes and heat shielding — metal edges, in a place that vibrates, with little slack. Insulation worn or heat-hardened against one of those edges is the cheapest thing on the list to find and to put right, which is reason enough to look there before reaching for a part.
Common causes
- Control lead chafed through against a clamp band, bracket edge, lifting eye or heat shield near the compressor housing
- Heat-hardened insulation that has cracked and let the conductor touch a grounded surface
- Lead pinched against the engine or a bracket when something was refitted in the area
- Water, coolant or salt in the valve connector bridging the control pin to a ground pin
- Crushed section of loom where the control conductor has contacted a grounded circuit
- Damaged or corroded inline connector between the valve and the module
- Internal short in the valve's solenoid winding
- Module driver output failed in the on state, which is the least likely cause here
Symptoms
- Check engine light, frequently with an underboost or boost-performance code alongside
- Sluggish acceleration and low or no boost pressure
- Persistently rich running, poor fuel economy and sooted spark plugs on engines with the air meter ahead of the turbo
- Rich fuel trim codes that survive smoke testing and find no vacuum leak
- A blown fuse, with something unrelated on the vehicle having stopped working at the same time
- Audible venting or hissing from the engine bay under load on vehicles with an atmospheric valve
- Valve not responding, or responding wrongly, when commanded with a bidirectional scan tool
- Symptoms present constantly rather than only on lift-off
Diagnostic steps
- 1.Let the engine cool before working near the turbocharger. The compressor housing and everything bolted near it stay hot enough to cause serious burns well after shutdown, and nothing on this list needs a hot engine.
- 2.Check the fuse for this circuit and note whether anything else on the vehicle has stopped working. A shared fuse that has given way tells you the short is real and roughly where in the loom to look.
- 3.Establish from service data whether this engine uses a recirculating or an atmospheric valve. That single fact explains whether to expect a boost complaint, a rich-running complaint, or both.
- 4.Inspect the valve connector for water, salt, coolant or corrosion bridging the pins, and check the seal and the connector body for cracks.
- 5.Trace the lead along its full route with the engine cool, paying attention to every place it passes a metal edge: clamp bands, brackets, lifting eyes, heat shield edges. Worn-through insulation is the cheapest outcome available here and it rewards a careful look rather than a quick one.
- 6.Unplug the valve and, with the ignition off, measure resistance from the control pin on the harness side to a clean chassis ground. A low reading with the valve out of the circuit puts the short in the wiring rather than the valve.
- 7.Measure the valve's solenoid winding across its own terminals and compare with specification. A reading well below specification, or continuity from either terminal to the valve body, condemns the valve.
- 8.Repair by cutting out the damaged length and splicing in new wire with proper insulation, then restore the clip or sleeving that was protecting it. Taping over the worn spot puts the conductor back against the same edge.
- 9.After repair, command the valve with a bidirectional scan tool and confirm it responds, then clear the codes and drive normally until the boost-related monitors complete.
Repair cost
$90 – $800
A chafe repair with new sleeving and a clip restored is $90 to $300 and is the outcome most of these turn out to be. Connector or pigtail replacement is $150 to $420. Repairing a crushed loom section is $220 to $600. Replacing the compressor outlet valve is $180 to $560 fitted, varying mostly with how buried it is. Diagnostic time is $90 to $200. Two follow-on costs are worth knowing about: a set of spark plugs fouled by weeks of rich running is $120 to $400, and on an engine that has been fed a rich mixture long enough the catalytic converter is at risk, which is a four-figure item on most vehicles.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with turbocharger bypass / diverter valve 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.