P0208 is a generic OBD-II powertrain fault code that means Injector Circuit/Open Cylinder 8. The ECM/PCM has detected an electrical problem in the fuel injector circuit for Cylinder 8.
P0208 does not automatically mean that the fuel injector itself is defective. The fault can also be caused by the injector connector, wiring, power supply, control circuit, fuse, or, less commonly, the ECM/PCM injector driver.
Fault Code Description
P0208 = Injector Circuit/Open Cylinder 8.
Code type: Generic OBD-II Powertrain Code.
Likely fault location: Cylinder 8 fuel injector, injector connector, injector wiring, injector power supply, injector control circuit, fuse or, less commonly, the ECM/PCM injector driver.
The word Open indicates an interruption or abnormal electrical condition in the Cylinder 8 injector circuit. It does not automatically identify the injector as the failed component.
What Does P0208 Mean?
The ECM/PCM controls the Cylinder 8 fuel injector through an electrical circuit and monitors the electrical behavior of that circuit. If the expected circuit condition is not detected, P0208 may be stored.
An open wire, excessive resistance, poor connector contact, loss of injector power, an internal injector fault, damaged wiring, or an ECM/PCM control problem can cause this code.
Symptoms of P0208
- Check Engine Light.
- Engine misfire.
- Rough or unstable idle.
- Hesitation during acceleration.
- Loss of engine power.
- Poor fuel economy.
- Hard starting.
- Engine vibration.
- Engine may stall in severe cases.
- Flashing Check Engine Light during a severe misfire.
Common Causes of P0208
- Faulty Cylinder 8 fuel injector.
- Open Cylinder 8 injector circuit.
- Broken injector control wire.
- Damaged injector connector.
- Loose or corroded electrical terminals.
- High resistance in the injector circuit.
- Loss of injector power supply.
- Blown injector or engine-control fuse where applicable.
- Damaged wiring near the engine.
- Intermittent connection caused by heat or vibration.
- Incorrect previous wiring repair.
- ECM/PCM injector driver fault.
How to Fix P0208
1. Scan the Vehicle
Confirm P0208 with a professional scan tool and check for additional injector, misfire, fuel-system, or electrical codes. Related codes can help determine whether the problem is isolated to Cylinder 8.
2. Identify Cylinder 8
Confirm the location of Cylinder 8 using vehicle-specific service information. Cylinder numbering and injector location depend on the engine configuration.
On many V8 engines, Cylinder 8 is located on the opposite bank from Cylinder 1, but the exact physical position must be confirmed for the specific engine.
3. Inspect the Cylinder 8 Injector
Inspect the injector body and connector for physical damage, contamination, loose terminals, corrosion, broken locking tabs, and poor electrical contact.
4. Inspect the Fuse Box
Check the applicable engine-control or injector power fuse. Depending on the vehicle, the fuse may be identified by an abbreviation such as INJ, EFI, ECM, PCM, ECU, ENG, FUEL, or another manufacturer-specific label.
The fuse number, rating, and location are vehicle-specific. Use the correct fuse-box diagram and wiring diagram rather than assuming that every vehicle uses the same fuse designation.
If a fuse is blown, determine the cause of the excessive current draw before repeatedly replacing the fuse.
5. Check Injector Power and Control
Use the correct wiring diagram to identify the Cylinder 8 injector power and control circuits. Verify the expected voltage and control signal according to the manufacturer's specifications.
Many injector systems use a common power supply with the ECM/PCM controlling the injector through the control side of the circuit. However, the exact design varies between vehicles.
6. Test Injector Resistance
Where permitted by the manufacturer, measure the resistance of the Cylinder 8 injector and compare it with the specification for the exact engine and injector type.
Do not apply a generic injector resistance specification to every vehicle because injector designs differ.
7. Check Injector Wiring
Inspect the complete circuit between the injector and ECM/PCM. Look for broken wires, damaged insulation, high resistance, short circuits, poor grounds, and wiring affected by heat, vibration, or previous repairs.
8. Verify the ECM/PCM Driver
If the injector, connector, fuse, power supply, and wiring are verified to be correct, test the ECM/PCM injector driver according to the manufacturer's diagnostic procedure before considering module replacement.
P0208 Diagnostic Signal Flow
↓
Fuse / Power Distribution
↓
Cylinder 8 Injector
↓
Injector Control Circuit
↓
ECM / PCM Driver
↓
Fuel Injection
↓
Cylinder 8 Combustion
P0208 OBD Live Data
Use an advanced scan tool to monitor engine RPM, cylinder misfire counters, fuel trims, injector-related parameters, engine load, commanded fuel conditions, and other available manufacturer-specific data.
If cylinder-specific misfire data is available, compare Cylinder 8 with the other cylinders.
Fuel trims can help determine whether an injector problem is producing a broader mixture effect, but fuel trims alone cannot prove that the injector is defective.
Live data should be combined with direct electrical testing because P0208 is primarily an injector circuit fault. An intermittent wiring or connector problem may not remain visible throughout a scan.
P0208 Electrical Testing
A professional diagnosis should verify the injector power supply and control circuit under the conditions specified by the manufacturer.
Depending on the vehicle, useful tests may include voltage testing, resistance testing, voltage-drop testing, circuit continuity testing, and injector control-signal analysis.
A test light, multimeter, oscilloscope, or specialized injector test equipment may be used depending on the system.
P0208 Injector Signal and Oscilloscope Testing
An oscilloscope can provide a more detailed view of the Cylinder 8 injector control signal. The exact waveform depends on the injector type and ECM/PCM driver strategy.
Simplified Injector Control:
Injector Power
│
▼
Injector
│
▼
ECM/PCM Driver
│
▼
Ground / Control Pulse
┌──────┐ ┌──────┐
Signal ─┘ └──────┘ └──────
ON ON
Injector Injector
command command
The displayed waveform should be compared with a known-good cylinder or the manufacturer's waveform and specifications. Do not use a generic waveform as a universal pass/fail specification.
Can a Bad Injector Cause P0208?
Yes. An internally defective Cylinder 8 injector can cause P0208, particularly if its electrical characteristics fall outside the expected range.
However, the injector should not automatically be replaced. The connector, fuse, power supply, wiring, and ECM/PCM control circuit should be tested first.
Can a Fuse Cause P0208?
Yes, where the injector power supply is protected by a fuse. A blown fuse or poor fuse-box connection can interrupt injector operation and trigger an injector circuit code.
If several injector-related codes appear at the same time, a common power supply, fuse, relay, or wiring problem becomes particularly important to investigate.
Is P0208 Serious?
P0208 can be serious if Cylinder 8 is not receiving the correct fuel delivery and the engine is misfiring.
A severe misfire can cause poor drivability, increased emissions, loss of power, and possible catalytic-converter damage on applicable gasoline engines.
Can I Drive With P0208?
Limited driving may be possible if the engine is running normally, but the fault should be diagnosed promptly.
If the Check Engine Light is flashing, the engine is severely misfiring, there is significant loss of power, or the engine is running very roughly, continued driving should be avoided.
P0208 Repair Cost
- Electrical diagnosis: approximately $50–$150+.
- Injector wiring repair: approximately $50–$250+.
- Injector connector repair: approximately $50–$200+.
- Fuel injector replacement: approximately $100–$500+ depending on the vehicle and injector type.
- Fuse or power-circuit repair: approximately $50–$200+ depending on the cause.
- ECM/PCM diagnosis or repair: can cost considerably more.
These are general estimates only. Actual repair costs depend on the vehicle, engine, injector type, parts prices, labor rate, and the underlying cause.
Common Repair Mistakes
- Replacing the injector without testing the circuit.
- Ignoring the injector connector.
- Failing to inspect the fuse box.
- Failing to verify injector power and control.
- Using a generic injector resistance specification.
- Ignoring wiring damage near the engine.
- Using the wrong cylinder numbering.
- Replacing the ECM/PCM before testing the injector circuit.
- Ignoring related misfire or injector codes.
- Repeatedly replacing a blown fuse without finding the cause.
Related Codes
- P0200 – Injector Circuit Malfunction.
- P0201 – Injector Circuit/Open Cylinder 1.
- P0202 – Injector Circuit/Open Cylinder 2.
- P0203 – Injector Circuit/Open Cylinder 3.
- P0204 – Injector Circuit/Open Cylinder 4.
- P0205 – Injector Circuit/Open Cylinder 5.
- P0206 – Injector Circuit/Open Cylinder 6.
- P0207 – Injector Circuit/Open Cylinder 7.
- P0308 – Cylinder 8 Misfire Detected.
FAQ About P0208
What does P0208 mean?
P0208 means Injector Circuit/Open Cylinder 8. The ECM/PCM has detected an abnormal electrical condition in the fuel injector circuit for Cylinder 8.
How do I fix P0208?
Confirm Cylinder 8, inspect the injector connector and wiring, check the applicable fuse and power supply, test injector power and control, measure injector resistance where applicable, and verify the ECM/PCM control circuit before replacing components.
Can wiring cause P0208?
Yes. An open wire, high resistance, damaged insulation, short circuit, or poor connector contact can interrupt Cylinder 8 injector operation and trigger P0208.
Can P0208 cause a misfire?
Yes. If Cylinder 8 does not receive the correct injector command or fuel delivery, it can misfire and cause rough running, vibration, hesitation, and loss of power.
Does P0208 mean the ECM is bad?
No. An ECM/PCM fault is possible, but it should generally be considered only after the injector, connector, fuse, power supply, wiring, and control circuit have been tested.
What is the difference between P0208 and P0308?
P0208 identifies an electrical fault involving the Cylinder 8 injector circuit, while P0308 indicates that the ECM/PCM has detected a misfire on Cylinder 8. The two codes can occur together, but they describe different diagnostic conditions.
Can a blown fuse cause multiple injector codes?
Yes. If several injectors share a common power supply protected by the same fuse or relay, a power-supply failure can cause multiple injector circuit codes simultaneously.
Should I replace all injectors when P0208 appears?
No. P0208 identifies the Cylinder 8 injector circuit. The affected injector and its circuit should be diagnosed individually unless testing reveals a broader system problem.
Final Takeaway
P0208 should be approached as a Cylinder 8 injector circuit fault, not automatically as a failed fuel injector.
The most reliable diagnosis is to inspect the Injector, connector, fuse box, power supply, wiring, control signal, and ECM/PCM driver in the correct sequence.
Because injector circuit designs vary between manufacturers and engines, always use the exact vehicle-specific wiring diagram, fuse-box information, electrical specifications, and diagnostic procedure when repairing P0208.