P0208 – Injector Circuit/Open Cylinder 8

P0208 is an OBD-II trouble code that points to a problem with the fuel injector circuit on cylinder 8. When this code sets, your engine computer has detected that the injector for cylinder 8 isn’t operating within its expected electrical range. You might notice rough running, misfires, poor fuel economy, or even a no-start in severe cases. While it can be as simple as a loose connector, it can also indicate a failing injector or wiring fault. Understanding what P0208 means helps you decide whether you can drive or need repairs right away.

What Does P0208 Mean?

P0208 stands for “Injector Circuit/Open – Cylinder 8.” Your engine control unit (ECU) constantly monitors the voltage and current going to each fuel injector. When it sees an electrical fault on the circuit controlling injector number 8, it stores P0208 and usually turns on the check engine light.

This code tells you there’s an issue in the electrical path for the cylinder 8 injector: the injector itself, the wiring harness, the connector, or the ECU driver. It does not automatically mean the injector is bad, but that the ECU doesn’t like what it sees on that circuit.

Quick Reference

• Code: P0208 – Injector Circuit/Open – Cylinder 8
• Severity: Moderate to high (misfire risk, possible engine damage over time)
• Common Symptoms: Rough idle, misfire, poor power, increased fuel use
• Typical Causes: Bad injector, wiring/connector issues, ECU driver fault
• Driveability: Often drivable short-term, but not recommended to ignore

Real-World Example / Field Notes

In the shop, I see P0208 most often on V8 trucks and SUVs where cylinder 8 is buried near the firewall. One common scenario: a customer comes in with a rough idle and flashing check engine light under load. Scan tool shows P0208 and a misfire on cylinder 8. A quick wiggle test on the injector connector makes the engine stumble more, and you can see the injector command dropping out on the scan data. In that case, the fix was a corroded connector and a short section of damaged wiring, not the injector itself.

On other vehicles, especially high-mileage engines, the injector coil itself fails open. Resistance checks show that injector 8 measures way higher than the others, confirming a bad injector. The key lesson: don’t throw parts at it. A few simple tests will usually separate a wiring issue from a failed injector.

Symptoms of P0208

• Check engine light on: P0208 usually sets a MIL, sometimes flashing during active misfire.
• Rough idle: A dead or weak cylinder 8 causes noticeable shaking at idle.
• Engine misfire: You may feel hesitation, stumbling, or a “chugging” sensation under load.
• Loss of power: With one cylinder not contributing properly, acceleration feels weak or uneven.
• Poor fuel economy: Misfires and unburned fuel can increase consumption.
• Hard start or no-start: In severe cases or with multiple issues, the engine may be difficult to start.
• Fuel smell from exhaust: A misfiring cylinder can send raw fuel into the exhaust, sometimes with popping sounds.
• Other misfire codes: Codes like P0308 (cylinder 8 misfire) often appear alongside P0208.

Common Causes of P0208

Most Common Causes

• Failed fuel injector (cylinder 8): The injector coil can open or short, causing incorrect resistance and triggering P0208.
• Damaged injector wiring: Broken, chafed, or shorted wires between the injector and ECU are extremely common, especially near hot exhaust components.
• Loose or corroded connector: Poor contact at the injector plug can intermittently open the circuit.
• Poor ground or power feed: If the shared power or ground for the injectors is weak, cylinder 8 may be the first to show a fault.

Less Common Causes

• Faulty ECU driver: The internal injector driver circuit in the ECU can fail, though this is less common than wiring or injector issues.
• Previous repair damage: Harness pinched, stretched, or incorrectly routed after engine or intake work.
• Rodent damage: Chewed wiring harness near the back of the engine or under the intake.
• Aftermarket modifications: Poorly installed performance injectors, tuning, or add-on modules interfering with injector control.

Diagnosis: Step-by-Step Guide

Before you start, you’ll want a basic scan tool, a digital multimeter (DMM), and ideally a noid light or lab scope. Access to a wiring diagram for your specific vehicle is very helpful. Safety first: work on a cool engine when possible and disconnect the battery when unplugging major connectors.

1. Confirm the code: Use an OBD-II scanner to verify P0208 is present. Check for related misfire codes (like P0308) or other injector circuit codes.
2. Inspect cylinder numbering: Identify which cylinder is #8 for your engine layout. Many DIYers test the wrong injector, especially on V-engines.
3. Visual inspection: Look closely at the cylinder 8 injector, connector, and nearby harness. Check for broken clips, oil contamination, melted insulation, or obvious damage.
4. Wiggle test: With the engine idling, gently wiggle the injector connector and harness. If the engine stumbles or the scan data for injector 8 changes, you likely have a connection or wiring issue.
5. Check injector resistance: With the key off, unplug injector 8 and measure resistance across the injector terminals using a DMM. Compare the reading to the spec and to other injectors. A wide difference usually indicates a bad injector.
6. Verify power and ground: With the key on, use a test light or DMM to confirm that the injector has proper power supply and that the ECU side of the circuit is being switched to ground when commanded.
7. Use a noid light or scope: Plug a noid light into the injector connector to see if the ECU is pulsing the circuit while cranking or running. No pulse suggests a wiring or ECU problem rather than the injector itself.
8. Continuity and short checks: If power or pulse is missing, check continuity from the injector connector back to the ECU connector. Look for open circuits, shorts to ground, or shorts to other wires.
9. Swap test (if accessible): On some engines, you can swap injector 8 with another cylinder and see if the code follows the injector. If P0208 becomes P020X on the new cylinder, the injector is the culprit.
10. Check Mode $06 data: Some scan tools allow you to view Mode $06, which can show misfire counts and injector performance data for individual cylinders, helping confirm an intermittent issue.

Pro tip: Always fix any obvious wiring or connector problems before condemning the ECU. ECU failures are rare compared to harness and injector issues, and replacing an ECU unnecessarily is expensive.

Possible Fixes & Repair Costs

The correct repair depends on what you find during diagnosis. Common fixes include replacing the cylinder 8 fuel injector, repairing or replacing a damaged injector connector, or repairing sections of the wiring harness. In rare cases, the ECU must be repaired or replaced.

• Replace cylinder 8 injector: Parts and labor typically range from $150–$400 per injector, depending on vehicle and access.
• Repair wiring/connector: Harness repairs can range from $100–$350, more if a large section of harness needs replacement.
• ECU repair or replacement: This can run from $400–$1,200+ including programming, depending on the vehicle.

Typical repair cost ranges for P0208 are around $150–$600 for most vehicles, but can climb higher on certain models with difficult access or dealer-only parts. Labor rates, injector brand/quality, and whether additional misfire-related damage is found will all affect the final cost.

Can I Still Drive With P0208?

In many cases, you can still drive with P0208 for a short period, but it’s not ideal. A dead or intermittent injector on cylinder 8 means that cylinder is running lean or not firing at all. That can lead to rough running, poor power, and potential catalyst damage from unburned fuel if the mixture is off. If the check engine light is flashing, that indicates an active misfire, and you should avoid driving except to get to a repair shop. Prolonged driving with this code can turn a simple repair into a much more expensive one.

What Happens If You Ignore P0208?

Ignoring P0208 can lead to long-term engine damage. A misfiring or lean cylinder can overheat valves and pistons, while unburned fuel can damage the catalytic converter. Over time, you may see worsening performance, increased fuel consumption, and more codes. What starts as a relatively minor injector or wiring issue can snowball into a multi-thousand-dollar repair if left unchecked.

Last updated: February 13, 2026

Vehicles Commonly Affected by P0208

P0208 can show up on any OBD-II vehicle with at least eight cylinders, but it’s especially common on V8 engines where cylinder 8 is harder to access and the wiring runs near hot exhaust components. You’ll often see this code on:

• Ford F-150, F-250, Expedition, and other V8-powered trucks and SUVs
• Chevrolet/GMC Silverado, Sierra, Tahoe, Suburban, Yukon, and similar LS-based V8 platforms
• Dodge/Ram 1500/2500 with HEMI V8 engines
• Jeep Grand Cherokee and other V8-equipped models
• Luxury brands like BMW, Mercedes-Benz, Lexus, and Audi with V8 engines

Even though it’s most often seen on trucks and larger SUVs, any V8 car, performance coupe, or full-size sedan can log P0208 if the injector circuit for cylinder 8 develops a fault.