P0306

Code

LAND ROVER P — Powertrain

ignition failure of Cylinder 6 Cylinder 7 ignition failure Cylinder

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 23 EN: 33 RU: 85

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Page language: EN

Causes

Ignition system fault on cylinder 6 (spark plug, ignition coil or wiring)
Fuel delivery problem to cylinder 6 (fuel injector clogged, faulty or electrical fault)
Low compression or mechanical issue in cylinder 6 (valve, piston, ring, timing)
Air intake/vacuum leak affecting cylinder air/fuel mixture
Faulty engine control module (rare) or sensor data (crank/cam position)
Contamination (oil or coolant) in cylinder 6

Symptoms

Check Engine Light (MIL) illuminated
Engine runs rough or vibrates, especially at idle
Reduced engine power and acceleration
Poor fuel economy and increased emissions
Possible hard starting or intermittent stalling
Occasional knock or ping if timing is off

What to check

Read and record all stored/ pending DTCs and freeze-frame data with a scan tool
Inspect spark plug condition and gap for cylinder 6
Swap ignition coil from cylinder 6 with another cylinder to see if misfire follows
Swap fuel injector from cylinder 6 with another cylinder (or test injector pulse) to check if misfire follows
Check fuel rail pressure and fuel supply
Measure injector resistance and operation (pulse width) with scan tool

Signal parameters

Cylinder misfire count for #6 (counts per test run)
Ignition coil primary/secondary waveform and voltages (V and Vpk)
Spark plug gap (mm/in)
Fuel injector resistance (ohms)
Injector pulse width (ms) at idle and under load
Fuel rail pressure (bar or psi)

Diagnostic algorithm

Connect a capable scan tool; record freeze-frame and live data. Note misfire counters and operating conditions when P0306 set.
Visually inspect ignition coil, spark plug and boot for cylinder 6. Replace visibly damaged components. Check plug gap and condition.
With the engine off, swap the ignition coil from cylinder 6 with a known-good cylinder. Clear codes and test-drive. If misfire follows coil, replace coil.
If coil swap does not move misfire, swap the fuel injector or use a stethoscope/electrical test to confirm injector operation. Replace or service injector if faulty.
Check wiring and connector continuity and resistance for coil and injector circuits. Repair any damaged wiring or poor connections.
Measure fuel rail pressure to confirm adequate supply and proper regulator function.
Perform a compression test and/or leak-down test on cylinder 6. Low compression points to mechanical repair (valve, head gasket, piston rings).
Inspect for intake manifold or vacuum leaks near cylinder 6 and correct as needed.
Verify camshaft and crankshaft timing; inspect timing chain/belt and variable timing components for faults.
If all hardware tests good, further test crank/cam sensor signals and PCM operation. Consider specialist diagnostics if intermittent electrical issues persist.
After repair, clear codes and road-test to confirm P0306 does not return and engine runs smoothly.

Likely causes

Worn, fouled or incorrectly gapped spark plug in cylinder 6
Failed ignition coil or coil pack on cylinder 6
Sticking or clogged fuel injector for cylinder 6
Damaged wiring or poor connector at coil or injector circuit for cylinder 6
Low compression in cylinder 6 due to valve seating, head gasket or piston ring issue
Intermittent crankshaft or camshaft position sensor signal causing misfire detection

Fault status

⚠️ Status

Misfire detected on cylinder 6 (DTC P0306). Check engine light set; engine may run rough and have reduced performance.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P0306 — ignition failure of Cylinder 6 Cylinder 7 ignition failure Cylinder