Which cylinder is number 8?

It depends on your engine, and the two dominant V8 conventions disagree. GM V8s number the passenger bank 2-4-6-8, which puts cylinder 8 at the very back on the passenger side. Ford modular V8s number the driver's bank 5-6-7-8, which puts cylinder 8 at the very back on the driver's side. Same code, opposite banks. Look up the cylinder-numbering diagram for your specific engine so you work on the right injector, and ignore the firing order for this purpose — it tells you when a cylinder fires, not where it sits.

What is the difference between P0208 and P0282 or P0283?

They cover the same circuit at different levels of detail. P0208 is the general form: something is wrong electrically on the cylinder 8 injector circuit. P0282 says the control line read LOW when it should have been high, which points at a short to ground or a shorted injector coil. P0283 says it read HIGH when the ECM commanded it low, which points at an open circuit or a short to power. If you have one of the specific codes alongside P0208, start there — it cuts your list of suspects roughly in half.

Is P0208 the injector or the wiring?

Either can cause it, but the wiring and connector fail more often. Cylinder 8 is the rearmost injector on most V8s, which means its connector runs hotter than the others and sits where cowl water tends to drain. Inspect it for corrosion, moisture, and backed-out pins, check the harness for chafing, then measure the injector's coil resistance. An open coil confirms the injector; a good reading points back to the circuit.

Can I keep driving with P0208?

The engine will run on seven cylinders, but a dead cylinder is a sustained misfire, and that can overheat and destroy the catalytic converter on that bank — a repair several times the cost of the injector. Drive directly to a shop, avoid hard acceleration, and pull over as soon as it is safe if the check engine light is flashing.

OBD-II trouble code

P0208: Injector Circuit/Open - Cylinder 8

The engine computer detected an electrical fault in the cylinder 8 fuel injector control circuit — usually wiring, a connector, or the injector coil. Cylinder 8 is the rearmost injector on nearly every V8, so confirm the fault before you start taking the intake off.

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: $50 – $1,500
DIY difficulty: Intermediate DIY

What does P0208 mean?

The engine control module (ECM) fires each fuel injector by pulsing its control circuit — battery voltage feeds one side of the injector while the ECM switches the ground on the other side for a precise number of milliseconds. It monitors the electrical feedback on that circuit, and when the voltage or current does not match what it commanded, it sets an injector circuit code. P0208 isolates that fault to the cylinder 8 injector circuit.

P0208 is the last member of the generic injector circuit/open family that runs from P0201 through P0208, covering cylinders 1 through 8. "Circuit/Open" is an electrical description rather than a verdict on the injector, and in practice the wiring side fails more often than the injector does: a chafed or broken wire, a corroded or backed-out connector pin, a poor ground, or a blown fuse. The injector's coil winding can also fail open. An injector that never gets pulsed leaves cylinder 8 with no fuel at all, so P0208 commonly arrives together with a cylinder 8 misfire (P0308), rough running, and clear power loss.

There is a second, more specific pair of codes covering the same circuit — P0282 (Cylinder 8 Injector Circuit Low) and P0283 (Cylinder 8 Injector Circuit High). Those report which direction the voltage went, which narrows the cause. P0208 is the general form and does not. Which one your ECM sets is a manufacturer choice; some vehicles set only P0208, some set only the low or high code, and some set both. If you have P0208 plus P0283, treat the more specific code as your starting point, because it tells you whether to look for an open or a short.

Cylinder 8 exists only on V8, V10, and V12 engines, and where it physically sits depends on the manufacturer. GM V8s number the passenger bank 2-4-6-8, placing cylinder 8 at the rear of the passenger side. Ford modular V8s number the driver's bank 5-6-7-8, placing cylinder 8 at the rear of the driver's side. Those are opposite banks. Look up the cylinder-numbering diagram for your specific engine before you remove anything, and do not try to deduce it from the firing order — that describes when a cylinder fires, not where it lives.

Practically, cylinder 8 is the hardest injector on a V8 to reach. It sits at the very back of a bank, frequently under the upper intake plenum, against the firewall or under the cowl. That location also explains why it sees more trouble than the front cylinders: it runs hotter, and it collects the water that drains off the cowl. Both are hard on a connector. Before committing to a teardown, test the circuit from the ECM connector end with the injector unplugged — a few minutes with a meter can rule out or confirm the wiring without touching a bolt.

Common causes

Broken, chafed, or shorted wiring to the cylinder 8 injector
Corroded, loose, or backed-out connector pins at the cylinder 8 injector
Open or shorted coil winding inside the cylinder 8 injector
Poor ground or a failed shared power feed serving the injectors on that bank
Blown injector fuse, which can affect cylinder 8 alone or an entire group
Water intrusion at the rear of the engine bay reaching the rearmost injector connector
Wiring disturbed or pinched during recent intake manifold or valve cover work
Rarely, a failed cylinder 8 injector driver inside the ECM/PCM

Symptoms

Check engine light on, sometimes flashing if cylinder 8 is dead
Rough idle and engine shaking
Loss of power and hesitation on acceleration
A cylinder 8 misfire, often as a companion P0308
Raw fuel smell or increased fuel consumption
Hard starting in some cases

Diagnostic steps

1.Confirm the code is P0208 and note every companion code, especially a cylinder 8 misfire (P0308) or the more specific P0282/P0283 pair, which tell you whether the circuit read low or high.
2.Identify which physical cylinder your engine calls number 8 and which bank it is on. GM V8s place it at the rear of the passenger bank; Ford modular V8s at the rear of the driver's bank.
3.Check the injector fuse and any relay feeding that bank's injector group first. It is the cheapest possible outcome and takes minutes.
4.Inspect the cylinder 8 injector connector and its wiring for corrosion, moisture, chafing, or backed-out pins, then wiggle-test while watching live data.
5.Measure the cylinder 8 injector's coil resistance with the key off and compare it to specification and to the other injectors. An open or out-of-spec reading condemns the injector.
6.Use a noid light or the scan tool's injector test at the cylinder 8 connector to confirm the ECM is actually pulsing the circuit.
7.Check the injector's power feed and ground at the connector with the key on. If there is no voltage, the fault is upstream and no injector will fix it.
8.Swap-test with a known-good injector if the resistance reading is borderline rather than clearly failed.
9.If the wiring, fuse, ground, and injector all test good but the drive pulse is missing, suspect the injector driver in the ECM/PCM — bearing in mind that replacement requires programming.

Repair cost

$50 – $1,500

A wiring or connector repair is often $50-$250, though tracing a chafed harness at the rear of a bank takes longer than at the front. A blown fuse can be a few dollars. A single fuel injector runs $60-$400 in parts plus 0.5-3 hours of labor — on a V8 or V10, reaching cylinder 8 under the intake manifold pushes labor toward the high end and usually adds intake gaskets, and a direct-injection unit costs more than a port injector. A failed ECM injector driver is rare and runs $500-$1,500 with programming. Diagnosis alone is typically $100-$180.

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.

Estimate your repair cost

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.