When the check engine light flashes and the car runs rough, you might ask what does p0316 mean. This OBD‑II code tells you cylinder six is misfiring, a problem that can cut power and raise fuel use. Ignoring it can damage the catalytic converter and cause emissions failures.
As of 2026 manufacturers still use the same detection thresholds.
Per SAE J2012 the ECU flags a misfire when cylinder contribution deviates more than 10 % for at least five seconds. Drivers usually feel a rough idle, see lower mileage, and sometimes experience stalling. Knowing the cause lets you fix the issue before costly repairs.
Let’s start with a clear definition of the problem and what you should look for.
What Does P0316 Mean
P0316 signals a misfire on cylinder six.
The ECU flags a contribution deviation over 10 %.
The code triggers the check engine light and rough idle.
It may reduce fuel economy and risk converter damage.
Problem / Pain Point
The misfire can stem from several components on cylinder six. Identifying the exact cause prevents unnecessary part replacement.
What triggers P0316
- An OBD‑II scanner reads the code and freeze‑frame data.
- A worn spark plug on cylinder six fails to ignite properly.
- A faulty ignition coil delivers inconsistent voltage to the plug.
- A clogged fuel injector reduces cylinder contribution below the threshold.
- A vacuum leak near the intake manifold affects cylinder six’s air flow.
What drivers notice
- A rough idle at low RPM is the most common symptom.
- Power loss during acceleration makes merging onto highways difficult.
- Fuel economy can drop by up to 15 % according to SAE data.
- The check engine light stays on after the misfire persists.
- Occasional stalling can occur when the engine load increases; secure the vehicle using a recovery point before working.
Core Explanation & Key Components
The ECU continuously compares each cylinder’s contribution to the overall air‑fuel mixture. When cylinder six falls outside the expected range, the code is stored.
How the ECU monitors misfire
- It measures voltage drop across the ignition coil during each firing.
- It monitors fuel injector pulse width and compares it to learned values.
- It tracks engine load, RPM, and coolant temperature to set thresholds.
- If the contribution deviation exceeds 10 % for five seconds, the code triggers per EPA OBD‑II regulations.
- The ECU stores freeze‑frame data for each occurrence to aid diagnosis; use an OBD‑II scanner to retrieve it.
Cylinder‑6 specific factors
- A fouled spark plug reduces spark energy and causes misfire.
- A cracked ignition coil boot leads to intermittent voltage loss.
- A restricted fuel injector limits fuel delivery to the cylinder.
- A leaking intake gasket introduces unmetered air, altering the mixture.
- A worn camshaft lobe can affect valve timing on that cylinder.
Related OBD‑II codes
- P0300 indicates a general misfire without specifying the cylinder; scan with an OBD‑II scanner to differentiate.
- P0351‑P0358 point to ignition circuit issues on each cylinder.
- P0171 or P0175 signal fuel system problems that can mimic misfire.
- P0420 relates to catalytic converter efficiency after prolonged misfire.
- P0322 indicates a knock sensor circuit fault that can affect timing.
| Component | Function | Typical Spec |
|---|---|---|
| Spark plug | Provides ignition for cylinder six | Gap 0.045 in (1.14 mm) |
| Ignition coil | Delivers voltage to spark plug | Resistance 0.5–2.0 Ω |
| Fuel injector | Supplies fuel to cylinder six | Flow 15–20 cc/min at 3 bar |
| ECU | Monitors and stores misfire data | SAE J2012 compliant |
A starter fluid test can confirm if the fuel system is delivering to cylinder six. If a part must be replaced, check lug nut cost for budgeting.
Step‑by‑Step Diagnosis Process
Secure the vehicle using a recovery point before lifting it. Follow this workflow to pinpoint the cause.
Diagnostic workflow
- Connect an OBD‑II scanner, read all DTCs, and record freeze‑frame data.
- Inspect the spark plug on cylinder six for wear, fouling, or incorrect gap.
- Test the ignition coil resistance; replace if outside 0.5, 2.0 Ω.
- Perform a fuel injector pulse test and check for blockage.
- Run a cylinder balance test at idle and 2000 rpm to identify the weak cylinder.
- Clear the codes, road‑test the vehicle, and verify the misfire does not return.
If a part must be replaced, check lug nut cost for budgeting. Following this workflow typically resolves the code within one to two attempts.
Mistakes to Avoid & Safety Guidelines
Common diagnostic errors can lead to unnecessary replacements or unsafe conditions.
Common diagnostic errors
- Do not spray starter fluid directly into the intake; use a proper cylinder contribution test instead.
- Avoid replacing parts based only on the code; confirm with a cylinder balance test.
- Do not ignore a vacuum leak; it can mimic misfire symptoms.
- Never work on a hot engine; allow it to cool before handling components.
- Skipping the road‑test after clearing codes can leave hidden issues unresolved.
Safety precautions
- Work on a cool engine to avoid burns from hot components.
- Disconnect the battery before testing ignition components to prevent electrical shorts.
- Wear safety glasses and gloves when handling fuel or cleaning spark plugs.
- Follow NHTSA safety guidance for proper vehicle lifting and support.
- Dispose of used spark plugs according to local hazardous waste rules.
