Will an injector flush fix P0289?

No, and this is worth being clear about because the advice circulates. P0289 is an electrical report: the computer measured the wrong voltage on a control wire. A clogged or restricted injector is a fuel-flow problem, and a partially blocked injector will still switch electrically exactly as it should — the computer would have nothing to complain about. Restricted flow shows up as a contribution or balance code such as P0290, not as a circuit code. Flushing the injectors on P0289 costs money and changes nothing. Diagnose the circuit: check the connector, the coil resistance, the control wire, and the power feed.

Why start at the connector rather than testing wires?

Because a circuit-high code usually means an open, and opens happen at joints far more often than in the middle of a wire. Wire is reliable along its length; terminals, splices, and connectors are where circuits come apart after years of heat cycling and vibration. That reasoning is at its strongest on this cylinder. On a V10, cylinder 10 is the last injector on the harness — downstream of every intermediate connector on that bank, at the tail of the loom where support brackets run out and the wiring moves most with the engine. Check terminal tension against a matching pin rather than by eye, because a terminal that has lost its grip still looks perfectly normal in the housing.

I have both P0288 and P0289 stored on the same cylinder. Which one is real?

Both, and they are telling you something more specific than either would alone. A circuit that reads low at some times and high at others is not two separate faults — it is one connection that is making and breaking. That is the signature of an intermittent: a terminal that has lost tension, or a corroded joint that conducts when cold and opens as the engine warms and moves. Do not buy an injector on the strength of it. Go to the connector, check terminal tension against a matching pin, look for corrosion and water, and wiggle-test the harness at operating temperature while watching live data.

Several injector circuit-high codes came up together. Do I need several injectors?

Almost certainly not. Injectors are normally fed in groups from a common supply, so several high codes appearing at once is the classic signature of a lost feed rather than several coincidental failures. Look at what the affected injectors share — a feed wire, a splice, a relay, or a fuse — and test that first. One repair usually clears the whole set. Replacing several injectors on the strength of several codes is how people spend a great deal of money and still have the codes, because the shared fault is still there when the new parts go in.

OBD-II trouble code

P0289: Cylinder 10 Injector Circuit High

The computer saw high voltage where it expected the cylinder 10 injector circuit to be pulled down. That means an open far more often than anything else — and on the last injector at the end of the harness, the most likely open is a connector, not a failed part.

Medium severityPowertrainFuel InjectorsDo not drive

Quick facts

System: Powertrain
Category: Fuel Injectors
Severity: Medium severity
Drivable: No — stop driving until repaired
Repair cost range: $50 – $1,800
DIY difficulty: Intermediate DIY

What does P0289 mean?

P0289 is the mirror of P0288. The engine control module (ECM) feeds battery voltage to one side of each injector and switches the ground on the other side. When the ECM commands cylinder 10's injector, the control line should be pulled down. P0289 sets when the ECM sees that line stay high — the voltage it expected to disappear did not, or voltage appeared where none should have been.

The two codes point in opposite directions and their suspect lists barely overlap. P0288 points at a short to ground, a shorted coil, or a driver stuck on. P0289 points overwhelmingly at an open circuit: a broken wire, a backed-out or corroded terminal, an open injector coil winding, or a lost power feed. A short to voltage is a distant second, and an ECM driver failed open is a distant third.

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, 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.

Here is what makes this particular code worth reading about rather than treating as a generic open. On a V10, cylinder 10 sits at the end of the line in two senses. It is the rearmost cylinder physically, at the back of its bank against the firewall. And it is at the end of the injector harness branch — the furthest point from the ECM, downstream of every intermediate connector on that bank, at the tail of a loom where support brackets run out and the wiring has the most freedom to move with the engine. Opens do not usually happen in the middle of a wire; wire is reliable along its length. They happen at joints — terminals, splices, and connectors — and the last injector on the harness has more joints upstream of it than any other on the engine, plus the least mechanical support at its own end. That is why on this code, a corroded or loose connector is the single most likely finding, and why the diagnosis should start there rather than with a meter on a length of wire.

Inspect the connector properly rather than visually. A terminal that has lost its grip looks perfectly normal sitting in its housing — check tension against a matching pin. Look for green or white deposits on the terminal faces, a backed-out pin that has pushed out of its lock, a hardened or displaced seal, and evidence that water has been in the housing. On a rear-of-bank connector that last one matters, because blocked cowl drains put water directly onto the back of a longitudinal engine.

Check the power feed early, because it is quick and it changes the scope. Injectors are normally fed in groups from a common supply, so a lost feed takes several injectors down together. If P0289 arrived alongside high codes for other cylinders on the same bank, stop working on cylinder 10 and go find what those injectors share — a feed wire, a splice, a relay, or a fuse. One repair clears the set. If P0289 stands alone, that is eliminated in two minutes.

One pattern is worth naming because it confuses people. If P0288 and P0289 have both been stored on this circuit at different times, that is not two faults and it is not a contradiction. A circuit that reads low sometimes and high at other times is a connection that is making and breaking — an intermittent, most often a terminal with lost tension or a corroded joint that conducts when the engine is cold and opens as it heats and moves. That combination should send you straight to the connector, not to the parts counter.

An open injector circuit means the cylinder gets no fuel at all — genuinely dead, not weak. On a ten-cylinder engine that is easy to miss, because nine cylinders still firing produce a vehicle that drives. Meanwhile the dead cylinder pumps oxygen-rich exhaust past the oxygen sensor and skews fuel trims on that bank, and any accompanying misfire sends raw fuel into an expensive catalytic converter. Trust the code rather than how the vehicle feels.

Common causes

Corroded, loose, or backed-out terminal in the cylinder 10 injector connector — the most likely single cause on this code
Open circuit in the cylinder 10 injector control wire from a break, a corroded splice, or vibration fatigue at the tail of the harness
Water intrusion from blocked cowl drains reaching the rearmost injector connector
Open injector coil winding on cylinder 10
Lost or open power feed to the injector, which usually affects a group of injectors rather than one
Corroded terminals in an intermediate connector between the ECM and the last injector on the bank
Harness chafing or heat damage where it passes the firewall, a bracket, or the exhaust at the rear of the bank
Control wire shorted to voltage (less common than an open on this code)
Wiring disturbed during recent intake manifold, plenum, or valve cover work
Failed cylinder 10 injector driver inside the ECM/PCM, failed open (uncommon — rule out everything else first)
Code misread or manufacturer-reassigned on an engine that has no tenth cylinder

Symptoms

Check engine light on, often flashing if cylinder 10 is completely dead
Rough idle and engine shake, frequently milder than expected because nine other cylinders mask it
Reduced power, most obvious under load or when towing
Companion misfire codes, commonly P0300 for a random or multiple misfire
Fuel trims skewed on the affected bank as the oxygen sensor reads the dead cylinder's excess oxygen
Hard starting or extended cranking
Poor fuel economy
No injector clicking heard at cylinder 10 when listening with a stethoscope
Fault that comes and goes with engine temperature or road surface, if a terminal has lost tension

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.Confirm which code you have. P0289 is circuit high and P0288 is circuit low; they call for almost entirely different tests.
3.Check whether both P0288 and P0289 have been stored on this circuit. Codes in both directions mean an intermittent connection making and breaking — go to the connector, not the parts counter.
4.Record every stored code. High codes on several injectors at once point at a shared power feed, splice, relay, or fuse rather than several failed injectors.
5.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.
6.Check the injector's power feed with the key on. No voltage at the feed side means stop looking at cylinder 10 and go find what the affected injectors share.
7.Inspect the cylinder 10 injector connector properly — terminal tension checked against a matching pin, corrosion on the terminal faces, a backed-out pin, a displaced seal, and any sign of water. This is the highest-probability finding on this code.
8.Check the cowl drains while you are back there, since a blocked cowl puts water directly onto the rearmost connectors on a longitudinal engine.
9.Measure the cylinder 10 injector's coil resistance. An infinite reading confirms an open winding and condemns the injector without further work.
10.Work back through each intermediate connector between the injector and the ECM. The last injector on a bank sits downstream of more joints than any other on the engine.
11.Check continuity of the control wire end to end, from the ECM connector to the injector connector, with both ends disconnected.
12.Wiggle-test the harness and each connector while watching live data or a meter, because opens at the tail of a harness are frequently movement-dependent.
13.Listen at the injector with a stethoscope while the engine runs. Silence at cylinder 10 with a good coil resistance reading points firmly at the control circuit.
14.If the wiring, feed, and injector all test good, suspect the ECM injector driver — but confirm everything else thoroughly first, because module replacement requires programming.

Repair cost

$50 – $1,800

A connector or terminal repair is very often the entire fix on this code, at $60-$350 — worth knowing before anyone orders parts, because a circuit-high fault usually means a joint has come apart rather than a component failing. Clearing blocked cowl drains, if that is what let water into the connector, costs essentially nothing and should be done regardless or the repair repeats. Tracing and repairing an open in a long ten-cylinder harness generally runs $150-$650, with the cost in locating it. 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. Injectors for V10 and V12 exotics and direct-injection applications commonly reach $250-$700 each. A failed ECM injector driver is uncommon and runs $500-$1,800 including programming. Diagnosis alone is typically $100-$200.

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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.