Error P0420 on Nissan Note: catalyst malfunction and solutions

Error P0420 on Nissan Note - one of the most common problems faced by owners of this compact car. Code indicates poor performance catalytic converter (can 1), which can lead to an increase in exhaust toxicity, a decrease in engine power and even problems with passing technical inspection. In most cases, the error is accompanied by a lit indicator Check Engine on the dashboard, but its reasons are not always obvious.

In this article we will look in detail at why P0420 on Nissan Note (including models E11 And E12), what symptoms help diagnose the problem, and what to do to fix it - from simple checks to complex repairs. We will pay special attention unique nuances of this model, for example, the effect of a faulty lambda probe on the operation of the catalyst and diagnostic features using a scanner Consult-III Plus. If you notice that the car accelerates worse and fuel consumption has increased, this article will help you understand the reasons.

What does error P0420 mean on Nissan Note?

Code P0420 stands for Catalyst System Efficiency Below Threshold (Bank 1) — that is, the efficiency of the catalyst in the first cylinder block is below the permissible threshold. B Nissan Note this code is activated when Engine ECU (electronic control unit) detects that the catalytic converter does not clean the exhaust gases sufficiently. The standard efficiency threshold for modern cars is no less than 90-95%.

It is important to understand that P0420 - this is not an instant error, but the result of long-term monitoring. The ECU analyzes data from oxygen sensors (lambda probes) before and after the catalyst over several engine operating cycles. If the difference in sensor readings is outside the normal range, the Check Engine. On Nissan Note with engines HR15DE or HR16DE this process can take from 1 to 3 weeks of active riding.

• 🔧 Main reason: wear or destruction of the catalyst (most often due to old age or mechanical damage).
• 🔥 Secondary causes: faulty lambda probes, air leaks in the exhaust system, rich/lean fuel mixture.
• ⚠️ Consequences of ignoring: increased fuel consumption, loss of power, inability to pass inspection.

On Nissan Note error P0420 often confused with P0430 (similar problem, but for the second cylinder block). However, in most modifications Note a single-row exhaust system is used, therefore P0420 occurs more often. Exception: all-wheel drive versions with engine MR20DD, where errors are possible for both banks.

P0420 Symptoms: How to Recognize the Problem

Error P0420 on Nissan Note does not always manifest itself clearly, especially in the early stages. However, there are several key signs that should alert the driver:

• 🚨 Check Engine light on: The most obvious symptom. The lamp may light up intermittently or continuously.
• 🛢️ Increased fuel consumption: The catalyst loses efficiency, and the ECU compensates for this by enriching the mixture.
• 🐢 Power drop: Particularly noticeable when overtaking or going uphill. Engine HR16DE It may become dull when accelerating.
• 💨 Unpleasant exhaust smell: If the catalytic converter is destroyed, the exhaust pipe may smell of hydrogen sulfide ("rotten eggs").
• 🔊 Extraneous sounds: rattling or rattling sounds under the bottom are a sign of destruction of the catalyst honeycomb.

On Nissan Note E12 (2012–2020) with system Eco Mode error P0420 may manifest itself as unstable engine operation at idle speed. This is due to the fact that the ECU tries to adapt to incorrect data from the lambda probes. In some cases, the car may even go into emergency mode, limiting the speed to 3000–3500 rpm.

⚠️ Attention: If together with P0420 errors appear P0130–P0167 (related to oxygen sensors), check the lambda probes first. Their malfunction in 60% of cases leads to a false activation of the catalyst code.

For accurate diagnosis, it is recommended to use a scanner that supports the protocol OBD-II with advanced features (for example, Launch X431 or Autel MaxiCOM). These devices allow you to view lambda sensor data in real time, which is critical for identifying the cause P0420.

Causes of error P0420 on Nissan Note

On Nissan Note error P0420 can occur for several reasons, and the catalyst itself is not always to blame. Let's consider the main factors:

Reason	Probability (%)	Diagnostic method
Catalyst wear or destruction	70%	Visual inspection, back pressure check
Malfunction of lambda probes (before or after the catalyst)	20%	Checking sensor voltage with a scanner
Air leak in the exhaust system	5%	Smoke generator or leak test
Rich/lean fuel mixture	3%	Diagnostics of injectors, mass flow sensor, fuel pump
ECU or firmware fault	2%	Flashing, error checking with other scanners

The most common reason is natural wear of the catalyst. On average, the service life of the original catalyst is Nissan Note amounts to 150–200 thousand km, but if low-quality fuel or oil is used, it may fail earlier. For example, antifreeze entering the combustion chamber (due to a broken cylinder head gasket) is almost guaranteed to destroy the catalyst within 1–2 thousand km.

The second most common reason is malfunction of oxygen sensors. On Nissan Note Lambda probes are installed Bosch or Denso, which become “contaminated” over time and begin to produce incorrect signals. Particularly vulnerable bottom sensor (after the catalyst), since it operates in a more aggressive environment. If its readings “freeze” at one level (for example, 0.1–0.2 V), the ECU erroneously detects a faulty catalyst.

What is "Bank 1" in P0420?

In OBD-II terminology, "Bank 1" refers to the first cylinder bank (usually the one containing cylinder 1). On most Nissan Note engines, including the HR16DE, this is the left side of the engine (when facing forward). The P0420 code always applies to the catalytic converter installed on this bank.

Diagnosing error P0420: step-by-step instructions

To pinpoint the cause P0420 on Nissan Note, follow this algorithm:

Read errors by the scanner and record freeze frame data (data at the time of the error)

Check the voltage of the lambda probes (should fluctuate in the range of 0.1–0.9 V)

Inspect the catalyst for mechanical damage

Check the exhaust system for leaks (air leaks)

Diagnose the fuel system (pressure, injectors, mass air flow sensor) -->

Start with reading errors scanner. Please note freeze frame data — this data shows the engine parameters at the time the error was recorded (revolutions, load, temperature, etc.). For example, if the error occurs at high speeds, this may indicate mechanical destruction of the catalyst.

Next check lambda probe readings:

• 🔋 Upper sensor (before the catalyst) must respond quickly to changes in the composition of the mixture (fluctuations 0.1–0.9 V).
• 🔌 Bottom sensor (after the catalyst) should show a more stable voltage (~0.7 V) if the catalyst is working.

If the lower sensor readings coincide with the upper one (for example, both fluctuate in the same range), this indicates catalyst malfunction. If the lower sensor is “silent” (shows 0 V or a constant value), most likely it itself is faulty.

To visually inspect the catalyst, remove oxygen sensor after it and shine a flashlight into the hole. If the honeycombs are clogged with soot or destroyed, the catalyst must be replaced. On Nissan Note With a mileage of more than 150 thousand km, a situation often occurs when the honeycombs simply crumble and rattle inside the case.

⚠️ Attention: When checking the exhaust system for leaks, pay special attention to exhaust manifold gasket And corrugation. On Nissan Note these elements often burn out, causing air leaks and false alarms P0420.

How to resolve error P0420: from simple to complex

How to solve the problem depends on the diagnosed cause. Let's look at them in order of complexity:

1. Replacing lambda probes

If the diagnostics showed a malfunction of the sensors, they must be replaced. On Nissan Note It is recommended to use original sensors Denso (article 22690-4M215 for the top, 22690-AL50B for the lower one) or high-quality analogues from Bosch. The cost of one sensor is from 2,500 to 5,000 rubles.

2. Elimination of air leaks

Check all exhaust system connections for leaks. Pay special attention to:

• 🔩 Exhaust manifold gasket (often burns out on engines HR16DE).
• 🔧 Corrugated (may crack from vibrations).
• 🛠️ Connecting the catalyst to the resonator (corrosion or loose clamps).

3. Cleaning or replacing the catalyst

If the catalyst is clogged but not destroyed, you can try to clean it with special liquids (for example, Liqui Moly Pro-Line Katalysator-Reiniger). However, this method only works 30% of the time. In most situations replacement is required.

Original catalyst for Nissan Note costs from 20,000 to 40,000 rubles. Alternative - installation universal catalyst (For example, Walker or Magnum) or flame arrester with a lambda probe decoy (but this is illegal for technical inspection).

4. Flashing the ECU

In rare cases, an error P0420 occurs due to incorrect ECU firmware. For example, after chip tuning or software update. The solution is to return the stock firmware or install a patch that disables the catalyst control (but this is fraught with problems with environmental regulations).

Repair cost and is it possible to drive with error P0420

The cost of repair depends on the cause of the malfunction:

Type of repair	Cost (RUB)	Working hours
Replacement of lambda probe (1 pc.)	3 000–8 000	1–2 hours
Eliminating air leaks	1 500–5 000	2–3 hours
Replacing the catalyst (original)	25 000–50 000	4–6 hours
Installing a flame arrester + snag	10 000–20 000	3–4 hours
Flashing the ECU	5 000–15 000	1–2 hours

Is it possible to drive with an error? P0420? Technically yes, but with caveats:

• ✅ Short term (1–2 weeks) - possible if there are no other symptoms (power failures, increased consumption).
• ⚠️ Long term - not recommended because:
• 🛢️ Fuel consumption increases (up to +15%).
• 🔥 Risk of catalyst overheating and fire.
• 🚗 There may be problems with passing the technical inspection.

⚠️ Attention: If ignored P0420 on Nissan Note with engine HR16DE, over time, the second lambda probe may fail (due to overheating) or even damage the exhaust manifold. Repairs in this case will cost much more.

Preventing error P0420 on Nissan Note

To extend the life of the catalyst and avoid errors P0420, follow these guidelines:

• ⛽ Use quality fuel (not lower than AI-95). On Nissan Note with engine HR15DE Low-quality gasoline leads to rapid clogging of the catalyst.
• 🔧 Change your oil promptly (every 10,000 km). Oil entering the combustion chamber (due to wear of rings or seals) destroys the catalyst.
• 🚗 Avoid short trips. The catalyst works more efficiently when the engine is warm (exhaust temperature > 400°C).
• 🔥 Don't ignore other errors (For example, P0300 — misfires). They can lead to overheating of the catalyst.
• 🛠️ Check the exhaust system for leaks every 50,000 km.

On Nissan Note with a mileage of more than 100,000 km, it is recommended to carry out diagnostics of lambda probes and a catalyst. You can do this yourself using a scanner ELM327 and programs Torque Pro (Android) or OBD Fusion (iOS). Pay attention to the following parameters:

• Lambda Voltage (Bank 1 Sensor 1/2) — sensor voltage.
• Catalyst Temperature — catalyst temperature (must be above 400°C when moving).
• Fuel Trim — correction of the fuel mixture (should be within ±10%).

Frequently asked questions (FAQ)

Can P0420 be cleared with a simple scanner reset?

Yes, you can reset the error, but it will return if the problem is not resolved. ECU Nissan Note fixes P0420 only after several cycles of sensor reading discrepancies. If after resetting the error appears again after 50–100 km, the catalyst or sensors are definitely faulty.

What happens if you remove the catalyst and install a blende?

Technically the car will drive, but:

• 🚫 Failure to pass inspection (increased CO/CH in the exhaust).
• 🔊 Exhaust noise will increase (especially at high speeds).
• ⚠️ Risk of damage to the exhaust system due to increased temperature.

On Nissan Note with ECU Hitachi decoys often work incorrectly, causing errors P0420 or P0130.

Which catalyst is better to choose for replacement: original or analogue?

Original catalyst (Nissan article number 20580-4M01A) is guaranteed to fit properly and meets environmental standards. However, its price is high (from 30,000 rubles). An alternative is catalysts from Walker (article 81396) or Magnum (article 93006NM). They are cheaper (15,000–20,000 rubles), but require a VIN compatibility check.

Can error P0420 appear after chip tuning?

Yes, if the firmware disables catalyst control or changes the fuel mixture parameters. For example, “sports” firmware often makes the mixture richer, which leads to overheating and destruction of the catalyst. The solution is to return the stock firmware or install a patch with the correct parameters for Nissan Note.

How to check the catalyst on a Nissan Note without a scanner?

You can use the mechanical method:

1. Warm up the engine to operating temperature.
2. Raise the vehicle on a lift or ramp.
3. Use a gloved hand to close the exhaust pipe (not completely!). If the pressure is strong (the hand is “pushed out”), the catalyst is clogged.
4. Shine a flashlight into the hole for the lower lambda probe - if the cells are destroyed or clogged with soot, the catalyst must be replaced.

⚠️ Be careful - the exhaust system is heated to high temperatures!