Error P0304 on Nissan: misfire in cylinder 4 - complete analysis

Error P0304 on your dashboard Nissan signals a problem that cannot be ignored. This code points to misfire in the fourth cylinder - a malfunction that can lead to serious consequences: from increased fuel consumption to damage to the catalytic converter. Model owners Qashqai, X-Trail, Juke and even GT-R encounter it regardless of mileage, but most often it appears on engines MR20DD, HR16DE And QR25DE.

What is the reason? Why does the fourth cylinder fail more often than others? And most importantly, how to fix the problem without overpaying for the service? In this article we will look at all possible scenarios: from banal wear of spark plugs to hidden wiring defects or mechanical damage. You will learn how to independently diagnose using a scanner. ELM327 or a multimeter, what spare parts are needed for repairs, and when you can’t do without the help of professionals. And for those who prefer visual instructions, we have prepared step by step videos with analysis of typical cases.

What does error P0304 mean on Nissan: code decoding

Code P0304 belongs to the series P0300–P0312, which indicates misfire in a specific cylinder. In this case, the number “4” indicates fourth cylinder (counting is carried out from the timing belt side). It is important to understand that this code is not the reason, but consequence other malfunction. Electronic control unit (ECU) fixes it when:

• 🔥 Crankshaft position sensor (CKP) registers uneven rotation (jerking).
• ⚡ The ignition system does not produce a spark at the right time.
• ⛽ The fuel mixture in the cylinder ignites untimely or does not ignite at all.
• 🔧 Mechanical problems (such as low compression) prevent normal combustion.

On Nissan with engines VQ or MR error P0304 often accompanied by other codes, for example:

• P0300 - random misfires (common code).
• P0171 — lean fuel mixture (may be due to air leaks).
• P0420 — low efficiency of the catalyst (consequence of long-term omissions).

If you ignore P0304, the consequences can be critical: from catalyst overheating (which leads to its melting) until damage to the piston group due to detonation. For example, on Nissan Almera N16 with engine QG15DE Frequent misfires lead to cracks in the exhaust manifold.

The main causes of error P0304 on Nissan

The causes of misfire in the fourth cylinder can be divided into three groups: Ignition, fuel system and mechanical problems. Let's look at each in detail.

1. Ignition system malfunctions

This is the most common reason P0304 - up to 60% of cases. Includes:

• 🔌 Worn or damaged spark plug (carbon deposits, cracks on the insulator, incorrect clearance). On Nissan Juke with engine HR16DE candles NGK IFR6T11 require replacement every 30–40 thousand km.
• 🔥 Breakdown of a high-voltage wire or ignition coil. For example, on X-Trail T32 with MR20DD coils often fail due to overheating.
• 📉 Ignition circuit low voltage (problems with wiring or ECU).

2. Problems with the fuel system

If there is a spark, but the mixture does not ignite, the following are to blame:

• ⛽ Clogged or faulty nozzle. On Nissan Qashqai J11 with MR20DD injectors Denso often clog due to low-quality fuel.
• 🔧 Low fuel pressure (faulty fuel pump or pressure regulator).
• 💨 Air leak through cracks in the intake manifold or gaskets (especially important for Teana J32 with VQ35DE).

3. Mechanical problems

Less common, but more critical:

• 🔩 Low compression in the fourth cylinder (worn piston rings, burnt valve).
• 🔗 Timing problems (stretched chain, worn sprockets). On Nissan Murano Z51 with VQ35DE the chain needs to be replaced every 150–200 thousand km.
• 🔥 Engine overheating, leading to deformation of the block head.

In practice 80% of cases errors P0304 related to the ignition or fuel system. Mechanical problems usually appear at mileages beyond 200 thousand km.

How to diagnose error P0304 yourself

For diagnosis you will need:

• 🔧 OBD-II scanner (For example, ELM327 or Launch CReader).
• 🔌 Multimeter to check the voltage.
• 🔍 Compressometer (if you suspect compression problems).
• 🛠️ Tool set for removing spark plugs/coils.

Step 1: Read Errors

Connect the scanner to the connector OBD-II (usually located under the steering wheel). Besides P0304, pay attention to the accompanying codes:

• P0300 - random omissions (indicates a general problem).
• P0171/P0174 — lean mixture (air leaks).
• P0420/P0430 — problems with the catalyst (consequence of omissions).

Step 2: Visual Inspection

Open the hood and check:

• 🔥 Spark plugs: carbon deposits, cracks, correct clearance (0.8–1.1 mm for most engines Nissan).
• 🔌 High voltage wires: melting, cracks.
• 💧 Oil or antifreeze leaks near the fourth cylinder (may indicate a broken cylinder head gasket).

Step 3: Checking the Ignition Coils

Use a multimeter to measure resistance:

• Primary winding: 0.5–2.0 Ohm (depending on the coil model).
• Secondary winding: 6–15 kOhm.

If the values are outside the limits, the coil is faulty. On Nissan Note E12 with HR16DE original coils Hitachi serve 100–150 thousand km.

Step 4: Compression Test

Remove the spark plug of the fourth cylinder, screw in the compression gauge and crank the starter. Normal values:

• Gasoline engines: 12–14 bar.
• Diesel engines: 25–35 bar.

The difference between the cylinders should not exceed 1 bar. If compression is low, repair is required cylinder head or piston group.

Step-by-step instructions for resolving error P0304

After diagnosis, proceed with repairs. Below is an algorithm of actions depending on the identified cause.

1. Replacing spark plugs

If the spark plugs are worn out or have carbon deposits:

1. Remove the ignition coils (disconnect the connectors and unscrew the bolts).
2. Unscrew the spark plugs with a spark plug wrench 16 mm (for most Nissan).
3. Install new spark plugs with the correct gap. For Qashqai J11 (MR20DD) are recommended NGK ILFR6H11 or Denso FK16HR11.
4. Tighten with torque 20–25 Nm (do not overtighten!).

2. Replacing the ignition coil

If the coil is broken or shows incorrect resistance:

1. Disconnect the power connector.
2. Unscrew the fastening bolt (usually 10 mm).
3. Remove the coil and install a new one. Original coils for X-Trail T31 (QR25DE) — Hitachi IGN-001.

3. Cleaning or replacing injectors

If the injector is clogged:

1. Remove the fuel rail (after releasing the pressure!).
2. Wash the nozzles in an ultrasonic bath or replace with new ones (Denso 23250-AL60A for MR20DD).
3. Check the injector resistance with a multimeter: it should be 12–16 Ohm.

4. Elimination of air leaks

If leakage is detected:

• 🔍 Check it out intake manifold gaskets And vacuum hoses.
• 🔧 Replace damaged elements. For Teana J32 manifold gaskets - Nissan 14045-4M000.
• 💨 Use smoke generator for accurate leak detection.

5. Repair of mechanical faults

If the problem is compression or timing:

• 🔧 Replacement of piston rings or valves (requires engine disassembly).
• 🔗 Replacing the timing chain with Nissan Juke (HR16DE) will cost 25–40 thousand rubles in the service.

Cost of repairs in service vs. do-it-yourself repair

Elimination prices P0304 vary depending on cause and model Nissan:

Type of repair	Cost of spare parts (₽)	Cost of work (₽)	Total (₽)
Replacing spark plugs (4 pcs.)	1 200–3 000	800–1 500	2 000–4 500
Replacing the ignition coil (1 pc.)	2 500–6 000	1 000–2 000	3 500–8 000
Cleaning injectors (kit)	1 500–4 000	2 000–3 500	3 500–7 500
Replacing the timing chain	8 000–15 000	15 000–25 000	23 000–40 000
Cylinder head repair (replacement of valves)	10 000–20 000	20 000–40 000	30 000–60 000

Do-it-yourself repairs will be cheaper, but require skills. For example, replacing spark plugs or coils with Nissan Almera G15 (K4M) takes 30–60 minutes and does not require special tools. But repairing the cylinder head or replacing the timing chain is best left to professionals.

What happens if you ignore P0304?

Long-term misfires lead to:

- Overheating and destruction of the catalyst (replacement will cost 30–80 thousand rubles).

- Increased wear of the piston group due to detonation.

- Increased fuel consumption by 15–30%.

- Loss of power and unstable engine operation at idle.

Common repair mistakes and how to avoid them

Many owners Nissan make mistakes that lead to reoccurrence P0304. Here are the most common:

⚠️ Attention: Never use candles with an inappropriate heat rating! For example, “cold” candles NGK BCPR6ES on Nissan GT-R (VR38DETT) will lead to detonation, and “hot” NGK BPR6ES - to glow ignition.

Error 1: Replacement of only one spark plug or coil. If the life of the elements is coming to an end, change set! For example, on Qashqai J10 (MR20DE) the coils fail almost simultaneously.

Error 2: Ignoring associated codes. If together with P0304 There is P0171 (lean mixture), first eliminate the air leak, otherwise the leaks will return.

Error 3: Incorrect spark plug tightening. Weak tightening leads to loss of compression, excessive tightening leads to damage to the threads in the cylinder head. Use torque wrench!

Error 4: Flushing injectors without checking their resistance. If the injector is “dead”, cleaning will not help - only replacement.

Error 5: Saving on spare parts. Cheap candles Beru or coils no-name will last 2-3 times less than the original ones.

Preventing error P0304 on Nissan

To avoid misfires:

• 🔧 Change the spark plugs every 30–50 thousand km (for iridium - up to 100 thousand km).
• ⛽ Refuel at trusted gas stations (bad fuel kills injectors).
• 🔥 Monitor the condition of the coils: If cracks or melting occurs, replace immediately.
• 💨 Check the tightness of the intake tract once every 20 thousand km.
• 📉 Monitor fuel pressure: normal for MR20DD — 3.5–4.0 bar.

On Nissan X-Trail T32 with MR20DD recommended every 60 thousand km carry out computer diagnostics for early detection of omissions. This will save you on expensive repairs.

Frequently asked questions (FAQ)

Is it possible to drive with P0304?

Short term - yes, but not recommended. Long-term driving with misfires leads to:

• 🔥 Overheating and destruction of the catalyst.
• 💥 Increased engine wear.
• ⛽ Increased fuel consumption by 20–30%.

If the error appears rarely (for example, during a cold start), you can postpone the repair for 1-2 weeks. If it lights up constantly, fix the problem immediately.

Why does P0304 only appear when cold?

This is typical for:

• 🔌 Worn spark plugs (the gap increases when cold).
• 🔥 Cracks in the ignition coil (when heated, microcracks are “healed”).
• ⛽ Air leak through rubber pipes (the rubber compresses when cold).

Check the spark plugs and coils, as well as the tightness of the intake tract.

What spark plugs are best for a Nissan with P0304?

The choice depends on the engine:

Engine	Recommended candles	Gap (mm)
HR16DE (Juke, Note)	NGK IFR6T11 or Denso FK16HR11	0.8–1.0
MR20DD (Qashqai, X-Trail)	NGK ILFR6H11 or Denso IXUH22I	0.9–1.1
VQ35DE (Teana, Murano)	NGK PLFR5A-11 or Denso FXE20HR11	1.0–1.1

Iridium spark plugs last longer (up to 100 thousand km), but cost 2–3 times more than regular spark plugs.

Could P0304 be caused by bad gasoline?

Yes! Low quality fuel leads to:

• ⛽ Clogging of injectors.
• 🔥 Formation of soot on candles.
• 💥 Detonation, which damages the pistons.

If after refueling at an unfamiliar gas station there are gaps, drain the fuel and flush the system. As a last resort, dilute gasoline with high octane (98th) in a 1:1 ratio.

How much does it cost to diagnose P0304 in a service?

The cost depends on the region and service station level:

• 🔍 Computer diagnostics: 500–1 500 ₽.
• 🔧 Compression check: 1 000–2 000 ₽.
• 💨 Search for air leaks (with smoke generator): RUB 1,500–3,000.

On average, comprehensive diagnostics will cost 3 000–6 000 ₽.