Fault code P0303 on cars Nissan indicates misfire in third cylinder. This error doesn't just cause a check light to light up on the dashboard - it directly affects engine performance, causing vibrations, loss of power and increased fuel consumption. Unlike general passes (code P0300), P0303 clearly indicates a problem in a specific cylinder, which narrows the range of diagnostics.

Owners Nissan Qashqai, X-Trail, Juke and other models with gasoline engines HR16DE, MR20DE or QR25DE encounter this error most often. The reasons can range from simple wear of the spark plugs to serious problems with the fuel system or engine mechanics. It is important to understand that ignoring P0303 leads to catalytic destruction of the converter — replacing it will cost many times more than timely repairs.

What does P0303 mean on Nissan?

Code P0303 stands for "Cylinder 3 Misfire Detected" — misfires were detected in the third cylinder. The electronic control unit (ECU) detects uneven engine operation when the air-fuel mixture in the cylinder does not ignite or burns incorrectly. The system analyzes data from the crankshaft, camshaft and oxygen sensors, comparing them with reference values.

Feature Nissan is that on some models (for example, Qashqai J10 with motor MR20DE) The ECU can issue P0303 even with minor deviations that would go unnoticed on other brands. This is due to more sensitive diagnostic algorithms. Important: misfires in one cylinder often provoke cascading errors - for example, P0420 (low catalyst efficiency) or P0171 (lean mixture).

  • 🔥 Consequences of ignoring: overheating of the catalyst, damage to the piston group, increase in fuel consumption by 15–30%.
  • ⚡ Symptoms: engine vibration, jerking during acceleration, smell of gasoline from the exhaust pipe, loss of power at low speeds.
  • 🛠️ Occurrence frequency: on engines HR16DE And MR20DE the error occurs 2 times more often than on QR25DE, due to the characteristics of the ignition system.

The main causes of misfire in cylinder 3

Reasons P0303 are divided into three groups: problems with ignition, fuel system and engine mechanics. On Nissan with a mileage of more than 100 thousand km, the wear of spark plugs and coils is in the lead, but there are often cases when air leaks or faulty injectors are to blame. Below is a ranked list of causes by frequency of occurrence (based on data from service centers).

Reason Frequency, % Difficulty in eliminating
Worn or damaged spark plug 45% Low (replacement in 30 minutes)
Ignition coil malfunction 30% Medium (requires diagnostics with a multimeter)
Air leak through the intake manifold gasket 15% High (needs a smoke generator or a soap solution test)
Dirty or faulty injector 8% Medium (ultrasonic cleaning or replacement)
Low cylinder compression 2% High (engine repair)

On Nissan Almera N16 And Primera P12 with motors QG16DE/QG18DE Often a combined problem occurs: wear of high-voltage wires + air leaks through cracks in the intake receiver. On diesel Navara And Pathfinder P0303 usually associated with faulty glow plugs or high pressure fuel injectors.

📊 Which Nissan model are you experiencing the P0303 code with?
  • Qashqai
  • X-Trail
  • Juke
  • Almera
  • Other model

Diagnosing error P0303: step-by-step instructions

To pinpoint the cause P0303, a comprehensive diagnosis will be required. Start with the simplest checks, gradually moving on to complex ones. On Nissan with the system CONSULT (For example, Teana J32) you can use dealer software to analyze parameters in real time, but for most models a regular scanner will suffice ELM327 and a multimeter.

Check the condition of the cylinder 3 spark plug (carbon deposits, gap)

Swap the ignition coils of cylinders 3 and 1 (if the error moves, the coil is to blame)

Measure the compression in cylinder 3 (standard: 12–14 bar for gasoline engines)

Check cylinder 3 injector resistance (normal: 12-15 ohms for most models)

Inspect the high-voltage wires for breakdown (sparks are visible in the dark with the engine running) -->

To check air leaks on Nissan with motors MR20DE/QR25DE effective method "pinching of hoses":

  1. Start the engine and let it warm up to operating temperature.
  2. Alternately pinch the rubber hoses going to the intake manifold (for example, from the crankcase ventilation valve or vacuum booster) with your hand.
  3. If, when any hose is pinched, the engine runs smoothly, look for a crack or a loose connection in this place.

⚠️ Attention: On Nissan Juke with turbo engine MR16DDT do not pinch the hoses for a long time - this can lead to the turbine protection triggering and an error P0234 (boost pressure exceeded).

How to fix misfire in cylinder 3?

The method of repair depends on the identified cause. Below are typical solutions for each of them, taking into account the features Nissan. For example, on Qashqai J11 with motor H4M replacing spark plugs requires removing the intake manifold, and X-Trail T32 - no. Always use original spare parts or approved analogues Nissan (for example, candles NGK IFR6T11 or Denso FK16HR11).

  • 🔧 Replacing spark plugs: On motors HR16DE And MR20DE The recommended interval is 30 thousand km (versus 60 thousand km in the manual). Use a torque wrench with a torque of 20–25 Nm.
  • ⚡ Checking the coils: The resistance of the primary winding should be 0.5–1.0 Ohm, the secondary winding should be 8–12 kOhm. On Nissan Note coils often fail due to oil entering through leaking valve covers.
  • 💨 Eliminating air leaks: On Nissan Tiida the weak point is the gasket between the intake manifold and the cylinder head. When replacing, use sealant Loctite 574.
  • ⛽ Cleaning the injectors: On motors QR25DE injectors are prone to contamination due to the nature of the injection system. For rinsing use Liqui Moly JetClean or Wynn's Injection System Purge.

If the problem is low compression, Nissan with aluminum block (MR20DE, QR25DE) often helps decarbonization (for example, a drug LAVR ML202). Procedure:

  1. Unscrew the candles, pour the product into the cylinders (50 ml each).
  2. Reinstall the spark plugs, but do not tighten them completely.
  3. Leave for 12 hours, then crank the engine with the starter without starting (to remove any remaining product).
  4. Start the engine and let it idle for 10-15 minutes.

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On Nissan Murano Z51 with motor VQ35DE After decoking, be sure to replace the oil and oil filter - the product has an aggressive effect on oil additives.

Common repair mistakes and how to avoid them

Many owners Nissan make typical mistakes when trying to eliminate P0303. For example, they change spark plugs without checking the coils, or clean injectors without diagnosing compression. This leads to re-occurrence of the error and additional costs. Let's look at the most common mistakes and ways to prevent them.

  • 🔄 Replacing spark plugs on cylinder 3 only: If the remaining spark plugs are worn out, the difference in the operation of the cylinders will provoke new errors. Solution: Change the complete set, even if visually the rest of the spark plugs look normal.
  • 🛑 Ignoring fuel mixture errors: If together with P0303 There is P0171 (lean mixture) or P0172 (rich mixture), eliminate them first. Solution: Check the mass air flow sensor (Mass Air Flow Sensor) and lambda probes.
  • 🔥 Using non-original coils: On Nissan coils from Hitachi or Denso serve 2–3 times longer than their Chinese counterparts. Solution: Buy spare parts with article numbers 22448-4M015 (for HR16DE) or 22448-AL51A (for MR20DE).
⚠️ Attention: On Nissan GT-R And 370Z with motors VR38DETT And VQ37VHR Replacing coils requires adaptation of the ECU. Without this, errors are possible P0300–P0306 even on new parts.
Why did error P0303 remain after replacing the spark plugs?

If after replacing spark plugs P0303 has not disappeared, check:

1. Gap between electrodes - on Nissan it should be 0.8–1.0 mm (even if a different one is indicated on the candle packaging).

2. Condition of the thread in the block head - if the spark plug was twisted skewed, the sealing ring could be damaged.

3. High voltage wire breakdown - on motors with individual coils (for example, HR16DE) there are no wires, but a spark can break through cracks in the coil insulation.

Preventing misfires on Nissan

Prevent P0303 easier than dealing with the consequences. Regular maintenance and attention to detail will save time and money. On Nissan with direct injection (MR16DDT, MR20DD) it is especially important to monitor the quality of the fuel - bad gasoline quickly damages the injectors.

  • ⏰ Replacement intervals:
    • Spark plugs - every 30–40 thousand km (even if the manufacturer indicates 60–100 thousand km).
    • Air filter - every 15 thousand km (on dusty roads - 10 thousand km).
    • Fuel filter - every 60 thousand km (on diesel Navara - 30 thousand km).
  • ⛽ Fuel: Use gasoline with an octane rating of at least 95 (for HR16DE/MR20DE) or 98 (for VQ35DE/VQ37VHR). On Nissan Leaf (electric car) error P0303 is impossible, but similar symptoms can be caused by a faulty inverter.
  • 🔧 Diagnostics: Once every 20 thousand km, read the errors with a scanner, even if the “check” is not lit. In the early stages P0303 may appear sporadically and not be recorded in the ECU memory.

On Nissan Patrol Y62 with motor VK56VD To prevent misfires, it is recommended to carry out cleaning the throttle valve And idle air valve adaptation. This prevents the formation of carbon deposits, which can cause uneven cylinder operation.

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Regular replacement of spark plugs and ignition coils is the key to P0303. On Nissan with a mileage of more than 150 thousand km, the risk of misfire increases 3 times due to natural wear of parts.

FAQ: Frequently asked questions about error code P0303 on Nissan

Is it possible to drive with P0303?

Short-term - yes, but no more than 200–300 km. Long-term driving with misfires leads to:

  • overheating and destruction of the catalytic converter (replacement cost - from 50 thousand rubles);
  • fuel getting into the oil, which reduces its lubricating properties;
  • increased load on the crankshaft and connecting rod bearings.

On Nissan Juke with motor HR16DE ignoring P0303 more than 500 km often ends water hammer due to fuel accumulation in the cylinder.

Why does error P0303 only appear when it is cold?

This is typical for two reasons:

  1. Wear of valve stem seals - on a cold engine, the oil is thicker and seeps into the cylinder, causing misfires. On Nissan Almera N16 this is a common problem after 120 thousand km.
  2. Coolant temperature sensor malfunction — The ECU receives incorrect data and incorrectly adjusts the mixture composition. Check the sensor resistance: at 20°C it should be 2–3 kOhm.
How much does it cost to fix P0303 in the service?

The cost depends on the reason and model:

Type of work Cost, rub. Note
Replacing spark plugs (set) 1 500–3 000 The cost of candles is 300–800 rubles/piece.
Replacing the ignition coil 3 000–6 000 Original reel - 4,000–7,000 rubles.
Cleaning injectors with ultrasound 4 000–8 000 On Nissan with direct injection - up to 12,000 rubles.
Replacing the intake manifold gasket 5 000–10 000 Includes manifold removal/installation.
Compression diagnostics 1 500–2 500 If the compression is below 10 bar, engine repair will be required (from RUB 30,000).
Could P0303 be caused by bad gasoline?

Yes, and this is one of the most insidious reasons. Low quality fuel leads to:

  • contamination of injectors (especially on Nissan with the system Direct Injection);
  • the formation of carbon deposits on valves and pistons (critical for engines VQ35DE And VQ37VHR);
  • a decrease in octane number, which causes detonation and misfires.

If the error appears after refueling, drain the fuel, wash the tank and replace the fuel filter. On Nissan GT-R This will require special equipment - independent flushing can damage the fuel lines.

How to reset error P0303 after repair?

Reset methods:

  1. Scanner: Connect ELM327 or Launch CReader, select the “Erase errors” function. On Nissan with the system CONSULT-3 Throttle adjustment may be required after reset.
  2. Disconnecting the battery: Remove the terminal for 10–15 minutes. Important: On Nissan with audio system Bose (For example, Teana J32) after this you will need to enter the radio code.
  3. Self reset: On some models (for example, Nissan Note) the error is reset after 3–5 successful cycles of starting the engine without skipping.

If the error returns immediately after resetting, the problem is not resolved. On Nissan with motors HR16DE/MR20DE this is often associated with leakage of the crankcase ventilation system - check the valve PCV (article 11810-4M000).