I have P0287 and P0290 together. Do I need two injectors?

Probably not, and that pattern is the most useful thing you have. Cylinders 9 and 10 sit next to each other at the rear of the same bank on the common numbering conventions, and two adjacent cylinders going weak at the same time is the classic signature of something they share rather than two coincidental failures. The specific candidates are a head gasket leaking between the two adjacent cylinders, an intake runner or plenum gasket leak feeding that end of the bank, and a fuel distribution problem at the far end of the rail. Compression- and leak-down-test both cylinders and smoke-test the intake before ordering a single part. Two injectors on this pattern is a well-travelled way to spend a lot and fix nothing.

Why check fuel pressure before replacing the injector?

Because on a V10 this is usually the last injector on the fuel rail, and a rail is a distribution system — any distribution system shows its weaknesses at the far end first. If rail pressure sags under high demand because the pump is tiring, the filter is restricted, or the regulator is marginal, the cylinder at the end of the run is the one that comes up short before the others do. That does not make the cylinder faulty; it makes it the cylinder that reports the problem earliest. A pressure test under load costs a fraction of what reaching this injector costs, and on this specific cylinder that ratio is the most lopsided anywhere in the injector block.

What is the difference between P0290 and the cylinder 10 injector circuit codes?

P0288 and P0289 are electrical statements about the injector's control wire — low voltage where high was expected, or high where low was expected. P0290 says nothing about wiring at all; it says the cylinder produced less power than its neighbors, measured at the crankshaft. That distinction decides your first move. If a circuit code is stored alongside P0290, fix the electrical fault and the balance fault usually clears with it. If P0290 is on its own, the wiring is fine and the cause is fuel delivery, ignition, or compression — tested in that order, cheapest and most definitive first.

Can I drive with P0290?

Short trips to a shop are generally fine, because the engine still runs. It should not be left alone, though. A cylinder burning its fuel incompletely sends unburned fuel into the exhaust, which can overheat the catalytic converter on that bank over time, and on a ten-cylinder engine that converter is not a cheap part. The masking effect is the real risk: nine healthy cylinders make the vehicle drive well enough that people postpone the repair for months while the converter takes the damage. If the check engine light starts flashing, stop driving and have the vehicle towed.

OBD-II trouble code

P0290: Cylinder 10 Contribution/Balance Fault

Cylinder 10 is producing less power than the rest, measured at the crankshaft. On a ten-cylinder engine the most valuable information is not this code by itself — it is which other contribution codes came with it, because the pattern tells you whether you have one weak cylinder or a shared problem at the back of a bank.

Medium severityPowertrainFuel InjectorsDrivable short-term

Quick facts

System: Powertrain
Category: Fuel Injectors
Severity: Medium severity
Drivable: Usually safe to drive short-term
Repair cost range: $100 – $4,000
DIY difficulty: Intermediate DIY

What does P0290 mean?

P0290 reports an outcome rather than a wiring condition. The engine control module (ECM) reads crankshaft rotational speed at high resolution through the crankshaft position sensor. Every power stroke gives the crankshaft a brief acceleration whose magnitude reflects how much work that cylinder produced, and the ECM compares all cylinders against one another. When cylinder 10 falls outside the allowed spread, P0290 sets.

Confirm your engine has a tenth cylinder first. That means a V10 or a V12 — the Ford 6.8L Triton V10, the Dodge and SRT V10s, VW and Audi V10s including the Touareg and Phaeton V10 TDI, the BMW S85, V10 and V12 exotics, and large industrial and marine diesels. On any smaller engine the code has been misread or reassigned by the manufacturer, and the manufacturer-specific definition always outranks the generic one.

The most useful thing this page can tell you is that on a ten-cylinder engine, the code you have matters less than the set of codes you have. A four-cylinder gives the balance monitor three peers to compare against and produces a thin picture. Ten cylinders produce a map, and that map is worth reading before any tool comes out of the box.

P0290 on its own means one weak cylinder, and the cause is confined to that cylinder: its injector, its plug and coil, or its compression. P0290 alongside P0287 — cylinders 9 and 10, which on the common numbering conventions sit next to each other at the rear of the same bank — is a completely different message. Two adjacent cylinders weak at the same time is the classic signature of something they share rather than two coincidental failures, and the shared candidates are specific: a head gasket leaking between the two adjacent cylinders, an intake runner or plenum gasket leak feeding that end of the bank, or a fuel distribution problem at the far end of the rail. Chasing two injectors on that pattern is a well-travelled route to spending a lot and fixing nothing. P0290 alongside contribution codes spread across both banks means neither cylinder nor bank is the story — go and look at whole-engine fuel supply: rail pressure, the filter, the pump, and fuel quality.

There is a second reason cylinder 10 deserves its own consideration, and it is physical. On a V10 this is the last cylinder on the engine, which usually also makes it the last injector on the fuel rail. A rail is a distribution system, and any distribution system shows its weaknesses at the far end first. If rail pressure sags under high demand — a tiring pump, a restricted filter, a marginal regulator — the cylinder at the end of the run is the one most likely to come up short before the others do. That does not make it the cylinder's fault. It makes it the cylinder that reports the problem first. So on this code specifically, check fuel rail pressure under load before condemning the injector, because a pressure test costs a fraction of what reaching that injector costs.

Once the pattern says one cylinder, the analysis is the standard one and the order is everything. Read the codes first: if P0210, P0288, or P0289 is stored alongside P0290, the injector circuit is electrically faulty and repairing it normally clears the balance fault with it. Those are statements about a wire; P0290 says nothing about wiring at all. If P0290 stands alone, the cause falls into three buckets that the crankshaft sensor cannot distinguish between. Fuel: a restricted, worn, or slow-opening injector. Ignition: on a gasoline engine, a worn plug or a coil breaking down under load. Compression: worn rings, a burnt or leaking valve, or a head gasket leak. Inspect the plug and swap the coil first, because that costs minutes and nothing. Compression- and leak-down-test second, because it is cheap and definitive. Buy the injector last — and on this cylinder, more emphatically than on any other in the block, because cylinder 10 is the hardest injector to reach on most V10 applications and the teardown can cost as much as the part.

On diesel applications the analysis narrows to fuel and compression only. Factory tools expose a per-cylinder balance rate — the size of the fuel correction the ECM applies to keep the engine smooth. A large, steady positive correction on cylinder 10 with healthy compression points at that injector. Diesel injectors degrade gradually rather than failing outright, which is exactly the decline a balance monitor is built to catch. Budget before ordering: the VW and Audi V10 TDI pump-injector units are among the most expensive injectors fitted to any passenger vehicle.

Cylinder numbering follows the same rule as the rest of this group. Ford's Triton V10 numbers the passenger bank 1 through 5 and the driver's bank 6 through 10, putting cylinder 10 at the very rear of the driver's side. Other V10s use the odd/even bank split familiar from American V8s. Confirm against your engine's diagram, not the firing order.

Common causes

Restricted, dirty, or internally worn cylinder 10 fuel injector
Injector opening late or producing a degraded spray pattern under load
Worn spark plug or a failing ignition coil on cylinder 10 (gasoline engines)
Low compression on cylinder 10 from worn rings, a burnt valve, or a valvetrain fault
Head gasket leaking between cylinders 9 and 10, which typically sets both contribution codes together
Intake plenum or runner gasket leak at the rear of the bank cylinder 10 sits on
Fuel rail pressure sagging under demand, which shows up first at the last injector on the rail
Restricted fuel filter, contaminated fuel, or a tiring fuel pump
Weak high-pressure fuel pump on a direct-injection or common-rail diesel engine
High-resistance wiring or a corroded connector at the cylinder 10 injector
Code misread or manufacturer-reassigned on an engine that has no tenth cylinder

Symptoms

Check engine light on
Rough idle and a shake at low RPM, often milder than the fault deserves because nine other cylinders mask it
Reduced power and hesitation under load, most noticeable when towing or climbing
Companion misfire codes such as P0300
Poor fuel economy
Hard starting or extended cranking, particularly on diesels
Excessive or black exhaust smoke on diesel applications
Fuel trims skewed on the affected bank

Diagnostic steps

1.Confirm your engine actually has a tenth cylinder. If it does not, the code has been misread or reassigned by the manufacturer — look it up against your specific make and model.
2.Read every stored code before touching anything, and read the pattern rather than just this code. P0290 alone means one cylinder; P0290 with P0287 means the two rear cylinders of a bank share a problem; contribution codes across both banks mean whole-engine fuel supply.
3.If P0210, P0288, or P0289 is stored alongside P0290, the injector circuit is electrically faulty — repair that first, and the balance fault normally resolves with it.
4.Confirm which physical cylinder your engine calls number 10. Ford's Triton V10 numbers the driver's bank 6-7-8-9-10; other V10s split odd and even cylinders across the banks.
5.Check fuel rail pressure under load before condemning anything. Cylinder 10 is usually the last injector on the rail, so it reports a distribution or supply shortfall before the other cylinders do.
6.Inspect the fuel filter at the same time, since a restriction shows itself at the far end of the rail first.
7.Run the scan tool's cylinder balance, injector contribution, or diesel balance-rate test and record how far cylinder 10 sits from the others, and how the neighboring cylinders compare.
8.On a gasoline engine, remove the cylinder 10 spark plug and compare it against the others. Heavy wear, fouling, or oil on the electrode can account for the weak contribution by itself.
9.Swap the cylinder 10 ignition coil with a neighboring cylinder, clear the codes, and drive. If the fault follows the coil, stop there.
10.Compression- and leak-down-test cylinder 10 before buying any fuel component, and test cylinder 9 at the same time if both contribution codes are stored — a leak between adjacent cylinders shows up as a shared reading.
11.Smoke-test the intake for a plenum or runner gasket leak at the rear of that bank.
12.Price the injector and confirm availability before committing, since ten- and twelve-cylinder engines — diesel V10s especially — carry injector prices well above mainstream V8s.
13.If fuel supply, ignition, and compression all check out, swap the cylinder 10 injector with one from a healthy cylinder and see whether the fault follows the injector.

Repair cost

$100 – $4,000

A spark plug or ignition coil on the weak cylinder is typically $100-$400 installed. Fuel filter or fuel pressure repairs generally land at $150-$800, and they belong early in the sequence on this cylinder because it is the last injector on the rail and reports supply problems first. A port fuel injector for a Ford Triton V10 or similar mainstream ten-cylinder runs $60-$200 in parts plus 1-3.5 hours of labor — cylinder 10 is the hardest injector to reach on most V10 applications, usually requiring the upper intake plenum to come off, which adds gaskets. Injectors for V10 and V12 exotics and direct-injection applications commonly reach $250-$700 each, and the VW and Audi V10 TDI pump-injector units are higher still. A high-pressure fuel pump is $600-$1,800. Mechanical causes — rings, a burnt valve, or a head gasket — start near $1,500 on a ten-cylinder engine and can exceed $4,000, and a head gasket leaking between cylinders 9 and 10 sits at the top of that band. Diagnosis alone is usually $100-$220, because the code calls for a sequence of tests rather than one measurement.

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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.