Error P0021 on cars Nissan Murano first generation (Z50 body) is one of the most common diagnostic codes indicating a system failure in the operation of the variable valve timing mechanism. This code is recorded by the engine controller when the camshaft position sensor shows a deviation from the calculated values set by the control system. As a result, the electronics block the normal operation of the motor, putting it in emergency mode.
The problem often occurs on series engines VR35DE or VQ35DE, which were installed on Nissan Murano Z50 between 2003 and 2008. Ignoring the signal can lead to serious consequences, including physical damage to the valves or piston group due to improper phase overlap. Insufficient oil pressure in the system is the main cause of P0021 on VQ series V6 engines., since the hydraulics cannot move the camshaft pulley correctly.
The essence of the malfunction and code P0021
Code P0021 stands for “Timing Chain - Valve Timing Advance Too Much, Bank 2.” In the context of the motor VQ35DE This means that the ECU (electronic control unit) has detected that the camshaft on the second bank of cylinders (right bank as viewed from the driver's seat) has opened the intake valves earlier than it should. The system attempts to correct the position through the solenoid, but does not reach the target angle.
It is important to understand that this does not always mean physically stretching the chain. Often the problem lies in the hydraulic phase control. The VVT-i solenoid receives a command from the ECU, opens, oil under pressure presses on the rotor blades, but if the pressure is low or the channels are clogged, the shaft does not reach the desired position. The result is desynchronization between the crankshaft and camshaft.
The main causes of the error
The first and most likely reason for Nissan Murano Z50 The phase regulator solenoid (OCV - Oil Control Valve) is dirty or jammed. Over time, the oil loses its properties and deposits form in it, which block the movable valve core. This causes the valve to become stuck in the open or closed position and the system is unable to adjust the advance angle.
The second reason is often mechanical wear of the timing chain or tensioner itself. Over a mileage of over 150,000 km, the chain inevitably stretches and the dampers wear out. The ECU tries to compensate for this stretching by shifting the phases, but when the correction limit is reached, it generates an error. It is also worth checking the condition of the oil pump, as wear on the gears reduces the pressure required for VVT-i to operate.
Vehicle symptoms and behavior
When the code appears P0021 The driver usually notices a significant decrease in engine traction and response. The car becomes sluggish, especially when accelerating. The indicator on the dashboard lights up Check Engine, and in some cases the oil pressure light may flash if the problem is due to insufficient lubricant level or pressure.
At idle speed, the engine may operate unstably, float or stall. This occurs due to the fact that the intake phase is disrupted and the mixture is supplied to the cylinders incorrectly. In cold weather, starting the engine may be delayed because the system cannot establish the correct starting phase for starting.
Diagnostics and testing of components
Diagnostics must begin by checking the level and quality of engine oil. A low level or the use of oil of the wrong viscosity (for example, too thick on a cold engine) will block the operation of the phase regulators. Check the condition of the filter - a clogged filter creates resistance to oil flow, which is critical for VVT-i operation.
Next, you should check the electrical circuits and the solenoid itself. Remove the VVT-i solenoid located on the right bank side of the cylinder head (bank 2). Inspect the mesh filter on its body - it often becomes clogged with metal shavings or sludge. Clean it with carburetor cleaner and check the winding resistance with a multimeter.
- Every 5000 km
- Every 7500 km
- Every 10,000 km
- According to manufacturer's regulations
Step-by-step instructions for troubleshooting
If the solenoid is faulty, it must be replaced or properly cleaned. To do this, disconnect the battery, remove the plastic decorative engine cover and unscrew the solenoid mounting bolt. Be careful not to damage the electrical connector. Before installing the new element, make sure the O-ring is in place and is not cracked.
☑️ Preparing to replace the solenoid
If the solenoid is ok, the problem may be deeper. It is necessary to remove the valve cover and visually assess the condition of the timing chain. Pay attention to the tensioner - if it is not extended, it means the chain is slack. Also check the condition of the chain guides for chips and wear.
What should I do if the error returns after a reset?
If error P0021 returns immediately after the adaptations are reset, this indicates a mechanical problem. The solenoid may open but not hold pressure, or the chain may already be so stretched that the ECU cannot tighten it. In this case, the timing chain and dampers need to be replaced.
Regulations for replacing the timing chain and hydraulic tensioner
Replacing the timing chain on the engine VQ35DE - This is a complex and time-consuming procedure that requires special tools. It is recommended to carry out this test when the mileage is around 200,000 km or when there are obvious signs of wear, such as a knocking sound at the top of the engine at idle speed. The process involves removing the attachments, exhaust manifold and oil pan.
When replacing the chain, be sure to also replace the hydraulic tensioners. Old tensioners may have a worn rod, causing the chain to sag immediately after starting. It is also recommended to replace the chain guides, as they are consumables and cannot be restored.
Features of the VVT-i system on the Murano Z50
VVT-i system on Nissan Murano operates over a wide speed range, providing a balance between power and efficiency. The ECU constantly monitors the position of the camshafts and adjusts it depending on the load. If the oil pressure drops below a critical threshold, the system disables the phase adjustment, locking the shaft in one position, which causes an error.
Particular attention should be paid to the quality of the oil used. For engines VQ series, it is critical to use low viscosity oils that meet manufacturer specifications. Thick oil does not have time to pass through the narrow channels of the solenoids during a cold start, which leads to false alarms of the diagnostic system.
Before installing a new solenoid, be sure to clean the seat on the cylinder head of old sealant and dirt to avoid air leaks or oil leaks.
Table of possible causes and diagnostic methods
| Component | Fault Symptom | Verification method | Recommendation |
| :--- | :--- | :--- | :--- |
| Solenoid VVT-i | Error P0021, jerky acceleration | Checking resistance, cleaning the filter | Replacement or flushing |
| Motor oil | Low pressure, knocking | Visual inspection, pressure measurements | Oil and filter change |
| Timing chain | Knocking in the engine, error after 150k km | Visual inspection, sag measurement | Replacement of chain and dampers |
| Hydraulic tensioner | Chain deflection, unstable idle | Checking the rod output, replacing | Tensioner replacement |
| Phase sensor | Signal failure, engine start | Open circuit check, oscillogram | Replacing the sensor |
Warnings and Safety Precautions
Work on diagnosing and repairing the timing system should be carried out only on a cold engine. Hot parts in the exhaust manifold and cylinder head can cause serious burns. In addition, when working on the vehicle's electrical equipment, be sure to disconnect the negative terminal of the battery.
Timely oil changes and the use of high-quality consumables extend the life of the VVT-i system and prevent the occurrence of error P0021 in 80% of cases.
When replacing the timing chain, the exact tightening order of the cylinder head bolts must be observed. Violation of the technology can lead to gasket burnout, antifreeze getting into the oil, or even deformation of the cylinder head. Use a torque wrench and follow the factory torque pattern.
Frequently asked questions (FAQ)
Is it possible to drive with error code P0021 on a Nissan Murano?
Technically, the car will drive, but in emergency mode. The engine does not develop full power, fuel consumption increases. Extended use may damage the circuit or solenoids.
How much does it cost to repair error P0021?
The cost depends on the reason. Replacing the solenoid will cost 3-5 thousand rubles including labor. Complete timing chain repair Nissan Murano Z50 can cost from 40 to 70 thousand rubles, including spare parts and labor.
Does the error change if you simply reset it with a scanner?
The error will reset temporarily, but will return immediately after several engine starting cycles if the physical malfunction (chain wear, dirt in the solenoid) is not eliminated.
Does oil quality affect error code P0021?
Yes, directly. Thick or old oil does not provide the required pressure and response speed of the VVT-i system, which is the most common cause of false errors.
Do I need to change both solenoids if an error occurs on one?
It is recommended to replace or clean both solenoids, since they operate under the same conditions and have the same life. If one gets stuck, the other will soon follow suit.