OBD-II trouble code
P0205: Injector Circuit/Open - Cylinder 5
This is the first code in the block that cannot appear on a four-cylinder, so the code itself tells you something about the engine. It also lands exactly where cylinder numbering stops being obvious — and it covers two completely different jobs depending on whether the engine is an inline five or a V.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $50 – $1,500
- DIY difficulty
- Intermediate DIY
What does P0205 mean?
P0205 means the module detected an electrical problem in the fuel injector control circuit for cylinder 5. The module feeds each injector battery voltage on one side and switches the ground on the other for a measured number of milliseconds, monitoring the circuit as it does so; when what it sees does not match what it commanded, it stores a code naming that cylinder. "Circuit/Open" is a description of the electrical condition, not of a part, and the wiring is a more frequent cause than the injector.
The first thing worth noticing is that this code carries information the lower-numbered codes in the block do not. Cylinder 5 does not exist on a four-cylinder engine, so P0205 is the point in the family where the code number itself narrows the vehicle down: it can only appear on an inline five, a V6, a V8 or something larger. That is genuinely useful when you are working from a code read remotely or from a description over the phone, before anyone has looked under the hood.
The second thing is that this is exactly where cylinder numbering stops being obvious, and it is the reason this page spends more effort on identification than on testing. On an inline engine, numbering is a row counted from the accessory-drive end and there is nothing to look up. The moment the engine has two heads, that certainty disappears. Manufacturers do not share a convention: some number all the cylinders on one bank and then all the cylinders on the other, some alternate from side to side following the firing order, and the result is that cylinder 5 can be at the front of a bank on one engine and in the middle on another. Reasoning about it is not good enough. On a V engine, looking up the numbering diagram for that specific engine family is the single highest-value action on this code, because the failure mode of getting it wrong is not a wasted five minutes — it is removing an intake plenum, replacing a healthy injector, reassembling, and finding the code still stored.
A small practical habit worth adopting alongside that: once you have identified the correct injector, mark it physically before any disassembly. The visual landmarks you used to count from tend to disappear as soon as the plenum comes off, and losing track at that point is how correct identification still ends up on the wrong port.
The third thing is that this code represents two genuinely different repairs, and the estimate should reflect that rather than averaging them. An inline five puts all five injectors in one row along the top of the head — accessible, comparable, and quick, much like a four-cylinder. A V engine may put cylinder 5 on a bank buried under an intake plenum, and then the same inexpensive injector arrives with hours of removal and a set of intake gaskets attached to it. Establishing the architecture before quoting is not pedantry; it is the difference between two estimates that are several hundred dollars apart.
One testing detail is specific to the V case and worth carrying. When you compare injector resistance readings, compare within a bank rather than across the engine. Coil resistance changes with temperature, and the two banks of a V engine do not necessarily sit at the same temperature — the bank tucked against the bulkhead on a transverse installation in particular runs and soaks differently from the one facing the airflow. A same-bank comparison is the fair test; a cross-engine one can make a healthy injector look marginal.
On consequences: an injector that is never pulsed leaves its cylinder unfuelled, so a cylinder 5 misfire code commonly appears alongside this one. The two together are one fault described from two directions, and the pairing points at the injector circuit rather than at ignition. A dead cylinder pumps unburnt fuel and air into the exhaust, which can overheat the catalytic converter — a part that costs considerably more than this repair. The engine will normally run and drive, so getting to a shop is fine, but keep the throttle light, do not tow or load the vehicle, and stop driving if the check engine light is flashing, which indicates the misfire is doing damage now.
Common causes
- Corroded or backed-out terminal at the cylinder 5 injector connector
- Chafed or broken conductor in the cylinder 5 branch of the injector loom
- Open coil winding inside the cylinder 5 injector
- Heat-damaged loom section on a V engine bank running under or beside the intake plenum
- Corroded injector supply splice serving the group that includes cylinder 5
- Blown fuse feeding one injector group on a multi-group supply arrangement
- Injector connector disturbed or left unmated after intake or plenum work
- Failed cylinder 5 injector driver inside the module, which is uncommon
Symptoms
- Check engine light, flashing if cylinder 5 has gone completely dead
- Rough idle and engine vibration
- Loss of power and hesitation under acceleration
- Companion cylinder 5 misfire code stored alongside
- Smell of unburnt fuel from the exhaust
- Increased fuel consumption
- Hard starting when cold
- Fault reappearing after an injector was replaced, when the wrong cylinder was identified
Diagnostic steps
- 1.Establish the engine architecture before you open anything, because this code covers two unrelated situations. An inline five has cylinder 5 as the last in a single accessible row and no bank question at all. A V6, V8 or larger splits the cylinders across two heads, and then which physical injector is number 5 depends entirely on the manufacturer's convention. Those are different jobs with different labour figures, and knowing which you have is step zero rather than a detail.
- 2.On any V engine, look up the cylinder-numbering diagram for that specific engine family and confirm it against the vehicle. Do not reason from the firing order, and do not assume the numbering matches the physical order along a bank. Some manufacturers number one entire bank and then the other; some alternate side to side. Getting this wrong means removing the wrong injector, which on a V engine is a full labour operation spent on a healthy part.
- 3.Mark the injector you have identified physically before disassembly begins. Once an intake plenum is off, the visual references you used to identify the cylinder are gone, and it is easy to lose track of which port you meant. A piece of tape on the correct injector body costs nothing and prevents the most common version of this mistake.
- 4.Inspect the cylinder 5 injector connector and its branch of the loom for corrosion, chafing and terminal retention. On an inline five this is straightforward top-of-engine access. On a V engine, note whether this injector is on a bank you can actually see — if it is not, skip ahead to electrical testing from the module end rather than removing hardware to perform a visual check.
- 5.Measure the cylinder 5 injector's coil resistance and compare it against the other injectors on the same bank rather than against the whole engine. On a V engine the two banks can sit at meaningfully different temperatures, and resistance moves with temperature, so a same-bank comparison is the fair one. An open reading condemns the injector outright.
- 6.Confirm the module is pulsing the circuit with a noid light or a scan tool output test at the cylinder 5 connector. A pulse present with a dead injector points at the part; no pulse with intact wiring points at the drive side. On engines where cylinder 5 sits under a plenum, do this test at the nearest accessible break in the harness before committing to teardown.
- 7.Check the injector power feed and fuse, and note which cylinders share them. On engines with five or more cylinders the injectors are usually grouped across more than one supply or driver, so establishing which group cylinder 5 belongs to tells you whether a single-cylinder code makes sense or whether you should be looking for a shared cause.
- 8.Verify after repair by clearing and driving, and watch for the companion cylinder 5 misfire code specifically. If the injector-circuit code stays away but the misfire returns, the electrical work is done and there is a separate mechanical or ignition fault on that cylinder to find.
Repair cost
$50 – $1,500
The spread on this code is driven almost entirely by engine architecture, so establish that before accepting an estimate. Diagnosis is $80 to $170, and confirming cylinder numbering on a V engine is part of that work. On an inline five, all injectors are accessible along the top of the head: a port injector is $60 to $250 plus half an hour to an hour. On a V engine with cylinder 5 under an intake plenum, the same part arrives with two to four hours of labour plus $30 to $120 in intake gaskets. Wiring and connector repairs are $50 to $220 where the harness is reachable and more where it is not. A direct-injection unit is $150 to $400 in parts. A failed module injector driver is uncommon and runs $500 to $1,500 with programming.
Estimate your repair
Run the numbers for your vehicle
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.