OBD-II trouble code
P0207: Injector Circuit/Open - Cylinder 7
Cylinder 7 only exists on eight-cylinder-and-up engines, so this is a truck, van, large SUV or V8 car — and the engine has enough injectors that they are driven in groups. Before condemning one, read what the other cylinders in that group are saying.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $70 – $1,800
- DIY difficulty
- Intermediate DIY
What does P0207 mean?
P0207 means the module detected an electrical problem in the fuel injector control circuit for cylinder 7. Each injector is fed battery voltage on one side while the module switches its ground for a measured number of milliseconds; the module watches that circuit and stores a code naming the cylinder when what it sees does not match what it commanded. "Circuit/Open" describes the electrical condition rather than a specific part, and wiring faults are more common than failed injectors.
The thing that makes this code its own subject rather than a copy of its siblings is the class of vehicle it appears on. Cylinder 7 requires an engine with at least eight cylinders, which in practice means a V8 — and V8s live in pickups, full-size vans, large SUVs, towing vehicles and V8 cars. That population brings two consequences that do not apply lower down the family.
The first is the shape of the repair. On the great majority of V8 engines the injectors sit underneath an intake manifold, so what looks on paper like replacing a modestly priced part is really an intake manifold operation. The scope includes manifold gaskets, the correct torque sequence on reassembly, and on many designs a coolant drain and refill because coolant passages run through the manifold casting. Quoting this as an injector replacement understates it substantially, and the honest way to present the job is as manifold-off access with an injector at the end of it.
The second consequence is more useful diagnostically, and it is the argument this page is built around. An engine with eight or more injectors does not drive each one from an isolated output with its own dedicated supply. Injectors are grouped — sharing feeds, fuses and often driver stages within the module — and the grouping is defined by the engine family. That gives you a test that simply does not exist on a four-cylinder: read the whole fault memory and see who else is complaining.
If several cylinders in the same group have stored injector-circuit codes, you are not looking at several failed injectors. You are looking at one shared cause — a feed, a fuse, a splice, a driver stage — and replacing injectors will not resolve it. If cylinder 7 is complaining alone while the rest of its group is silent, the shared hardware is proven good by those siblings and the fault is confined to cylinder 7's own branch: its connector, its short run of wire, or its coil. Either way the fault memory has narrowed the search before you have picked up a meter, and on an engine where access costs hours, that is worth more than it would be anywhere else in this family.
There is a related habit worth adopting given the access cost. Because the injector loom on a V8 lives under the manifold in trapped heat and is never inspected in normal service, degradation accumulates unseen for years. When the manifold is off, inspect the whole exposed length rather than only the branch you came for. Hardened, cracked or discoloured insulation elsewhere in that run is very likely to be the next fault, and dealing with it while access is already paid for is nearly free — whereas finding it in six months means buying the entire labour operation a second time. For the same reason, command the injector and confirm the circuit responds while the harness is still exposed, rather than reassembling on faith.
One measurement note: compare resistance readings within the bank rather than across the engine. An eight-cylinder engine gives you a healthy sample size, which makes an outlier obvious without a specification figure, but the two banks of a V8 do not necessarily sit at the same temperature and coil resistance follows temperature.
On consequences: an injector that never receives a pulse leaves its cylinder unfuelled, so a cylinder 7 misfire code commonly appears with this one — the same fault seen from the electrical and the mechanical side. Unburnt fuel and air passing into the exhaust can overheat the catalytic converter, and a V8 typically has one per bank, so the damage concentrates on the converter serving the dead cylinder. There is also a load consideration specific to this vehicle class: these are the vehicles people tow with, and towing on seven cylinders puts sustained heavy load on a compromised engine and its exhaust. The vehicle will normally drive to a shop unloaded, but do not tow with it, keep the throttle light, and stop driving if the check engine light is flashing.
Common causes
- Corroded or backed-out terminal at the cylinder 7 injector connector, under the intake manifold
- Heat-degraded insulation on the injector loom running beneath the intake manifold
- Open coil winding inside the cylinder 7 injector
- Failed shared supply feed or splice serving the injector group that includes cylinder 7
- Blown fuse feeding one injector group, which normally takes several cylinders with it
- Failed driver stage in the module serving a group of injectors rather than one
- Connector left unmated or damaged during previous intake manifold work
- Chafed conductor where the loom passes a manifold stud or bracket
Symptoms
- Check engine light, flashing if cylinder 7 has gone completely dead
- Rough idle and a distinct loping or uneven beat from the exhaust
- Noticeable loss of power, most obvious under load or when towing
- Companion cylinder 7 misfire code stored alongside
- Injector-circuit codes on other cylinders in the same group, pointing at a shared cause
- Smell of unburnt fuel from the exhaust
- Increased fuel consumption
- Hard starting when cold
Diagnostic steps
- 1.Read the whole fault memory and look specifically for injector-circuit codes on other cylinders before you look at cylinder 7 at all. Engines with eight or more injectors do not drive them individually from a single output — they are grouped, sharing supply feeds and often driver stages. That means a cluster of injector codes across one group is a shared cause, and a single code among quiet siblings is that cylinder. This is a distinction the low-numbered codes in this family cannot offer you, because a four-cylinder has no group to compare against.
- 2.Establish which cylinders share a group with cylinder 7 from service data, then check whether those cylinders are complaining. If they are, stop looking at injectors and go to the shared feed, the fuse and the driver stage that serves them all. If they are silent, the fault is confined to cylinder 7's own branch and you have narrowed the search substantially without a single measurement.
- 3.Confirm which physical cylinder is number 7 on this engine family. On a V8 the numbering convention varies between manufacturers — some number one bank completely and then the other, some alternate side to side — and cylinder 7 can be at either end of a bank depending on the design. Getting this wrong on a V8 means removing an intake manifold to replace a healthy part, so look it up rather than reasoning from firing order.
- 4.Price the job as an intake manifold operation rather than an injector replacement until you know otherwise. On most V8 engines the injectors sit under an intake manifold, so the realistic scope includes manifold gaskets and, on many designs, a coolant drain and refill because coolant passages run through the manifold. That is the actual job, and quoting an injector alone will be wrong by a wide margin.
- 5.Inspect the injector connector and its branch of the loom once the manifold is off, and inspect all of the harness you can see rather than only cylinder 7's part of it. This loom lives under the manifold in trapped heat, never gets looked at, and degrades quietly. Anything hardened, cracked or discoloured in that run is a future fault you are already paying the labour to reach.
- 6.Measure the cylinder 7 injector's coil resistance and compare it against the other injectors on the same bank. Eight-cylinder engines give you a good sample size for this, which makes an outlier obvious without needing a book figure — but keep the comparison within the bank, since the two banks of a V8 do not necessarily sit at the same temperature and coil resistance moves with temperature.
- 7.Command the injector with a scan tool output test while the harness is exposed, before the manifold goes back on. Reassembling and then discovering the fault is unresolved means paying the entire labour operation twice, and on this engine class that is the most expensive avoidable mistake available. Confirm the circuit responds while access is free.
- 8.Fit new manifold gaskets and follow the specified torque sequence on reassembly, and refill and bleed the cooling system if coolant was drained. On a V-configuration intake, a reused gasket or an out-of-sequence torque is a route to a vacuum leak or a coolant leak that presents as a new set of codes entirely.
Repair cost
$70 – $1,800
Treat this as an intake manifold operation with an injector at the end of it, because that is what it usually is on a V8. Diagnosis is $90 to $200, and reading the group pattern in the fault memory is part of that. A port injector is $60 to $300 in parts, but the labour to reach it under a manifold is two to five hours, plus $40 to $180 in manifold gaskets and coolant on designs where coolant passages run through the casting — realistically $450 to $1,100 all in. A shared feed, splice or fuse problem affecting a whole group is often cheaper than that at $120 to $400, which is exactly why reading the other cylinders' codes first pays. A direct-injection unit is $180 to $450 in parts. A failed module driver stage runs $600 to $1,800 with programming.
Estimate your repair
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Open the Repair Cost Estimator with fuel injector 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.