OBD-II trouble code
P0268: Cylinder 3 Injector Circuit High
The cylinder 3 injector control circuit read high — normally an open circuit or a short to battery voltage. Cylinder 3 gets little or no fuel, so expect a misfire and address it promptly.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $50 – $1,500
- DIY difficulty
- Intermediate DIY
What does P0268 mean?
P0268 is the mirror image of P0267. The engine control module (ECM) fires the cylinder 3 injector by pulling its control wire to ground; the module also monitors that wire and expects to see the voltage drop when it commands a pulse. P0268 sets when the voltage stays high — the ECM asked the circuit to go low and the circuit refused.
There are two ways a circuit can refuse. The first is an open: a broken wire, an unplugged or corroded connector, or an injector coil with a broken winding means the ECM's ground pull never reaches anything, so the voltage never drops. The second is a short to battery voltage: another power source is feeding the control wire and holding it up, so the ECM cannot pull it down. Both read high, and separating them is the first real work of the diagnosis.
The useful thing about a high code compared with a low one is that the candidate list is genuinely short. A low reading can come from three different faults that all look alike on a scan tool. A high reading means either nothing is connected or something is actively pushing the voltage up — and a simple continuity check across the injector, plus a voltage check on the control wire with the ECM unplugged, tells you which within minutes.
With the circuit high, cylinder 3 is receiving little or no fuel, so a misfire is nearly guaranteed and P0303 often appears alongside. Raw air and unburned mixture entering the exhaust can overheat the catalytic converter, which is why this is not a code to postpone. As with the rest of this block, confirm which physical cylinder your manufacturer calls number 3 before testing — on V engines the numbering is frequently not what you would assume.
Common causes
- Open circuit in the cylinder 3 injector control wire (broken conductor or corroded splice)
- Open coil winding inside the cylinder 3 injector
- Injector connector unplugged, backed out, or with a spread or corroded terminal
- Control wire shorted to battery voltage or to another powered circuit
- Chafed harness contacting a powered wire or terminal
- Loss of the switched power feed to the injector (blown fuse or failed relay on that bank)
- Rarely, a failed cylinder 3 injector driver inside the ECM/PCM
Symptoms
- Check engine light on, sometimes flashing under load
- Dead or badly weak cylinder 3 with a rough, shaking idle
- Misfire codes such as P0303 or P0300 alongside P0268
- Significant loss of power and hesitation
- Raw fuel smell or unburned fuel odor from the exhaust
- Poor fuel economy
- Hard starting or extended cranking
Diagnostic steps
- 1.Confirm P0268 and record companions. P0267 alongside it points at an intermittent or wiring-level fault rather than a straightforward open; P0303 confirms the cylinder is genuinely down.
- 2.Identify cylinder 3 for your engine in the service information before testing anything.
- 3.Inspect and reseat the cylinder 3 injector connector. A backed-out pin or a connector never fully latched after prior service is a frequent and free fix.
- 4.Unplug the injector with the key off and measure coil resistance. An infinite or very high reading confirms an open winding — replace the injector.
- 5.With the key on and the injector unplugged, verify battery voltage is present on the feed side of the connector. No voltage means the problem is upstream — a fuse, relay, or feed wire — and no injector will fix it.
- 6.Check the control wire for continuity from the injector connector back to the ECM connector with both ends disconnected. No continuity confirms an open in the harness.
- 7.With the ECM connector disconnected, check the control wire for unexpected voltage. Voltage present there means the wire is shorted to a power source, which must be found and repaired.
- 8.Once wiring and injector both test correct, use a noid light or the scan tool's injector test to confirm the ECM is actually pulsing the circuit before considering the module.
Repair cost
$50 – $1,500
Reseating a connector or repairing a broken wire is often $75-$250, and a bad connector sometimes costs nothing but time. A single fuel injector runs $60-$400 in parts plus 0.5-3 hours labor depending on whether it sits on top of the intake or beneath it. A blown fuse or failed relay is usually under $100. A failed ECM injector driver is uncommon and runs $500-$1,500 with programming. Diagnosis alone is typically $75-$150.
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.
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.