OBD-II Diagnostic Trouble Code
P0311 — Cylinder 11 Misfire Detected
P0311 means the ECM detected misfires on cylinder 11, based on crankshaft speed variation during that cylinder's firing event. It can only set on engines with eleven or more cylinders, which are rare in modern on-road trucks, so if it shows on a 6- or 8-cylinder engine, check that the scan tool and ECM calibration are correct before chasing parts.
Severity 4/5
Truck-relevant
Stop within 50 mi
Severity
Stop within 50 mi
Cylinder 11 Misfire Detected
Code
P0311
Category
Powertrain
Subsystem
Ignition
Truck-relevant
Yes
What this means for truckers
Stop within ~50 miles on a Cummins X15, Detroit DD15, PACCAR MX-13. Driving longer risks damaging adjacent components (turbo housing, head gasket, aftertreatment) and turning a $300 fix into a $3,000 fix.
Before you replace parts — try this first
P0311 on the Ignition system is most often ignition coil, spark plug or injector failure on cylinder 11 (12-cylinder engines) — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
On a 12-cylinder engine: rough running, vibration under load, check-engine light, reduced power and higher fuel use. On a truck with fewer than 11 cylinders, the code points to a scan tool decoding error, the wrong ECM calibration or a software fault, not a real cylinder 11 problem.
Common causes
- CommonIgnition coil, spark plug or injector failure on cylinder 11 (12-cylinder engines) ($150–$1400)
- OccasionalWiring or connector fault in the cylinder 11 coil or injector circuit ($100–$450)
- OccasionalScan tool misreading the code or the wrong ECM calibration for the engine's cylinder count ($0–$400)
- RareLow compression on cylinder 11 from a valve or ring problem ($1500–$6000)
How to fix
Confirm the engine's cylinder count and re-read the code with an OEM-level scan tool
When to use: Always first, especially on engines with fewer than 12 cylinders
Swap the ignition or injector components on cylinder 11 with another cylinder to see if the fault follows
When to use: On a confirmed 12-cylinder engine
Inspect and test the cylinder 11 harness and connector
When to use: When the misfire is intermittent
Do compression or leak-down tests on cylinder 11
When to use: When fuel and ignition test good
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P0300 — Random/Multiple Cylinder Misfire Detected
- → P0301 — Cylinder 1 Misfire Detected
- → P0302 — Cylinder 2 Misfire Detected
- → P0303 — Cylinder 3 Misfire Detected
- → P0304 — Cylinder 4 Misfire Detected
Frequently Asked Questions
Can I drive with code P0311?
Drive with caution. P0311 is severity 4 — stop within ~50 miles. Most commercial diesel codes at this severity (turbo, fuel rail, transmission solenoid) can damage adjacent expensive components if left unrepaired. Get to a service location before highway-speed loads.
How much does it cost to fix P0311 on a commercial truck?
Total repair cost ranges varies depending on the root cause. The cheapest fix is usually the first one listed below — Ignition coil, spark plug or injector failure on cylinder 11 (12-cylinder engines) — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P0311 fail a DOT inspection?
P0311 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P0311 and related codes?
P0311 is closely related to: P0300 (Random/Multiple Cylinder Misfire Detected), P0301 (Cylinder 1 Misfire Detected), P0302 (Cylinder 2 Misfire Detected), P0303 (Cylinder 3 Misfire Detected). These codes share the same subsystem (ignition) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P0311 is set without the companions, the issue is more isolated.
How do I prevent P0311 from coming back after a repair?
For P0311 (Cylinder 11 Misfire Detected), prevention centers on the ignition system. Use OEM-spec injectors and spark plugs (gas). Address fuel quality issues immediately — bad fuel kills injectors. Cylinder balance test annually for early warning.