P0306 on 2002-2005 Land Rover Freelander: Cylinder 6 Misfire Causes and Fixes

What's Unique About the 2002-2005 Land Rover FREELANDER

The key challenge with a P0306 on the Freelander's 2.5L KV6 engine is physical access. Cylinder 6 is part of the rear bank of cylinders (2-4-6), which is tucked under the plastic upper intake manifold (plenum). This design means that simple jobs like changing a spark plug or ignition coil for that cylinder become significantly more labor-intensive, as the entire plenum assembly must be removed first. Furthermore, this manifold houses two Variable Intake System (VIS) motors, which are a notorious failure point on the KV6 engine and can only be serviced with the plenum removed, adding another layer to the repair.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Flashing or solid Check Engine Light
• Engine stumbling or hesitation, especially under acceleration.
• Rough or vibrating idle
• Noticeable loss of power
• Potential for engine stall
• Rattling noise from the intake manifold area (may indicate a related VIS motor issue).

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil Coils are a common wear item, and heat in the confined space of the rear cylinder bank can shorten their lifespan. The rear bank uses three coil-on-plug units.
   How to confirm: After accessing the coils, swap the cylinder 6 coil with another cylinder's coil (e.g., cylinder 4). Clear the codes and run the engine. If the code changes to P0304, the coil is faulty.
   Typical fix: Replace the faulty ignition coil. It is strongly recommended to replace all three coils on the rear bank at the same time due to the labor involved in accessing them. Many owners replace all six.
   Est. part cost: $30-$70 per coil
2. Worn or Fouled Spark Plug 🔴 High Probability → Shop Spark Plug
   How to confirm: Once the intake plenum is removed, inspect the spark plug for cylinder 6. Look for wear, oil fouling, coolant contamination (white residue), or heavy carbon deposits. The correct gap is approximately 1.0 mm.
   Typical fix: Replace the spark plug. It is best practice to replace all six spark plugs at the same time 🎬 Watch: Step-by-step spark plug replacement guide for the Freelander V6., especially given the labor to access the rear bank.
   Est. part cost: $5-$20 per plug
3. Vacuum Leak (Intake Manifold Gaskets) 🟡 Medium Probability The plastic intake manifold and its associated rubber gaskets can become brittle with age and heat cycles, leading to leaks. The process of removing and reinstalling the plenum for other repairs can also disturb old gaskets, causing a leak.
   How to confirm: With the engine running, spray a small amount of brake cleaner or an unlit propane torch around the intake manifold gaskets. If the engine RPM changes, a leak is present. A professional smoke test is the most definitive method.
   Typical fix: Replace the upper and lower intake manifold gaskets. This should be done anytime the plenum is removed. Torque the manifold bolts to 18 Nm (13 lbf.ft) and the support brackets to 10 Nm (7.5 lbf.ft) during reassembly.
   Est. part cost: $40-$100 for a gasket set
4. Clogged or Faulty Fuel Injector ⚪ Low Probability → Shop Fuel Injector
   How to confirm: Swap the cylinder 6 fuel injector with another cylinder and see if the misfire code follows. This is a labor-intensive test. A professional can also test injector flow and spray pattern. An injector's resistance can be tested with a multimeter and should be 14.5 ± 0.7 ohms.
   Typical fix: Replace the faulty fuel injector.
   Est. part cost: $50-$150 per injector

Rare But Worth Checking

• Low Engine Compression: The KV6 engine can be prone to head gasket issues, partly due to its wet-liner design. A compression test is crucial if ignition and fuel-related causes are ruled out. A low reading on cylinder 6 points to a mechanical problem like a bad valve, piston rings, or a leaking head gasket.
• Faulty VIS (Variable Intake System) Motors: While not a direct cause of a single-cylinder misfire, the two VIS motors on the intake manifold are a very common failure point. Since the manifold must be removed for a P0306, it is the perfect time to inspect them. A failed VIS motor can cause rattling noises and a significant loss of power at specific RPM ranges, which can be mistaken for misfire symptoms.
• Cracked Fuel Tank Pump Flange: TSB SWA09013 mentions that a cracked fuel tank pump flange can cause fuel delivery issues, potentially leading to misfires (including P0306) along with lean codes like P0171 and P0174. This would likely cause misfires on multiple cylinders, not just one.

Diagnosis Steps

1. Confirm the code is P0306 using an OBD-II scanner. Note any other codes present, especially other misfires or lean codes.
2. Plan for the removal of the upper intake manifold (plenum) to gain access to the rear cylinder bank. This involves disconnecting the air intake, multiple vacuum hoses, and electrical connectors.
3. CRITICAL: While the intake plenum is removed, inspect and test the two Variable Intake System (VIS) motors. 🎬 See how to test, dismantle, and rebuild your VIS motors. Check for oil contamination and test the actuator arms for free movement. A failure here causes rattling and power loss.
4. Once the plenum is removed, swap the ignition coil from cylinder 6 with the coil from cylinder 4.
5. Temporarily reassemble enough to run the engine. Scan for codes again. If the code is now P0304, the ignition coil is the confirmed problem.
6. If the code remains P0306, the coil is likely good. Proceed to inspect the spark plug from cylinder 6. Look for damage, fouling, or incorrect gap (should be ~1.0mm). Compare it to a new plug.
7. If the plug and coil are good, the next step is to perform a compression test on cylinder 6 to rule out mechanical engine problems. A healthy KV6 should have compression above 150 PSI, with minimal variation between cylinders.
8. If compression is good, the issue may be with the fuel injector. This is less common and harder to test for a DIYer. Check injector resistance; it should be 14.5 ± 0.7 ohms.
9. During reassembly, always use new intake manifold gaskets to prevent vacuum leaks. Tighten the main manifold bolts to 18 Nm and the rear support bracket bolts to 10 Nm.

Parts You'll Likely Need

• Ignition Coil (OEM #NEC000110L) — This is the most frequent cause of a single-cylinder misfire on this engine.
  Trusted brands: Bosch, Delphi, NGK, Atlantic British
  OEM price range: $60-$90
  Aftermarket price range: $30-$70
• Spark Plug (OEM #NLP100290L) — Spark plugs are a primary ignition component and a common wear item. They should be replaced if they are worn or fouled.
  Trusted brands: NGK (PFR6N-11 is a common equivalent), Bosch
  OEM price range: $15-$25
  Aftermarket price range: $5-$20
• Intake Manifold Gasket Set — These gaskets must be replaced whenever the intake manifold is removed to prevent performance-robbing vacuum leaks.
  Trusted brands: Victor Reinz, Mahle
  OEM price range: $70-$120
  Aftermarket price range: $40-$100

Related Codes That Often Appear With This One

• P0300 — Indicates random/multiple misfires. If seen with P0306, it suggests the problem may be more widespread, like a vacuum leak or fuel delivery issue affecting all cylinders.
• P0302, P0304 — These are misfire codes for the other cylinders on the same rear bank. Seeing them together could point to an issue specific to that bank, or a more systemic problem.
• P0171, P0174 — These codes indicate the engine is running lean on Bank 1 and Bank 2, respectively. They often accompany misfire codes when caused by a large vacuum leak (e.g., intake manifold gasket) or a fuel delivery problem, as noted in TSB SWA09013.
• P1471, P1472 — These codes relate to faults with the VIS motors. While they don't always trigger the Check Engine Light, they may be stored in the ECM and indicate a problem that should be addressed while the intake manifold is off.

Technical Service Bulletins (TSBs) & Recalls

• SWA09013: Mentions that various misfire codes, including P0306, can be stored in relation to fuel system issues causing engine hesitation or stalling.
• 19/01/06/NAS: Details diagnostic procedures for the Variable Intake System (VIS) motors located on the intake manifold. A fault here can cause performance issues and is best addressed when the manifold is removed for other service. It notes a VIS fault code will not illuminate the MIL by itself.

Platform-Specific Known Issues

• Access to the rear bank of cylinders (2, 4, 6) is blocked by the upper intake manifold/plenum, significantly increasing labor time for what would otherwise be a simple repair. Forum users confirm there is no shortcut and the manifold must be removed.
• The Variable Intake System (VIS) motors, located on the manifold, are a very common failure point. They can cause rattling noises and power loss. TSB 19/01/06/NAS addresses their diagnosis. Since the manifold must be removed to fix a P0306, it is critical to inspect and likely repair the VIS motors at the same time.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance — expected: 14.5 ± 0.7 ohms at 20 °C (68 °F). Failure: A reading significantly outside this range, or one that differs greatly from the other injectors.
• Fuel Rail Pressure — expected: 3.5 bar (51 lbf/in²). Failure: Low fuel pressure can cause lean conditions and misfires on multiple cylinders.

Scan Tool Commands That Help

• TestBook / T4: Misfire Detection / Cylinder Balance Test — The official Land Rover diagnostic tool (TestBook or T4) can run specific routines to analyze misfire counts per cylinder in real-time, which is more advanced than a generic OBD-II scanner. This can help confirm if the misfire is constant or intermittent under specific load/RPM conditions.

Wiring & Ground Locations

• C1772 — The 3-pin female electrical connector for the ignition coil on cylinder 6.. This is the direct connector for the cylinder 6 ignition coil. Checking for battery voltage on Pin 1 (BU wire), ground on Pin 2 (B wire), and the ECM switching signal on Pin 3 (NK wire) is a key diagnostic step.
• Header Earth 0553 (K108) — An earth header point where multiple engine sensor and actuator grounds are consolidated.. The Engine Control Module (ECM) grounds are routed through this header. A poor connection here can cause erratic behavior and seemingly unrelated codes, including misfires.
• Splice Joint 10 (SJ10) — An inline splice in the engine wiring harness.. This splice provides the ground path for the ignition coils on the rear bank (2, 4, and 6). Corrosion or a break in this splice would affect all three cylinders on that bank, but could present intermittently on just one.

Real Owner Repair Stories

• LandyZone forum user 'kim_lombard' (2003 Freelander KV6, 78,000 miles) — Getting multiple misfire codes (P0306, P0304, P0301). Runs fine for 5-10 minutes after a reset, then throws codes when accelerating from a stop. Scan tool shows 'OL-Fault' (Open Loop Fault) at the same time.
  ❌ Tried (didn't work) New spark plugs, Inspecting coils and wires, New fuel filter
  ✅ What actually fixed it The user did not post the final resolution, but the symptoms of running fine in closed-loop and then faulting in open-loop under acceleration strongly point towards a fuel delivery or major vacuum leak issue that the ECM cannot compensate for, rather than a simple coil/plug failure.

OEM Part Supersession History

• NEC000070 / NEC000070L → NEC000110 / NEC000110L — Updated part design for ignition coils.
  Heads up: The early (NEC000070) and late (NEC000110) style coil packs are physically different and not interchangeable. Vehicles from mid-2002 onwards use the later 'late type' packs.

Model Year Variations Within This Range

• 2002-2003: There was a changeover period for ignition coil design around mid-to-late 2002. A 2002 or early 2003 model could have either the 'early' (NEC000070L) or 'late' (NEC000110L) style coils. Visual identification is necessary before ordering parts.