P0021 – Camshaft Position “A” – Timing Over-Advanced or System Performance (Bank 2)

Code P0021: Definition and Explanations

The generic diagnostic trouble code P0021, titled “Camshaft Position ‘A’ – Timing Over-Advanced or System Performance (Bank 2)”, is a powertrain-related code. It applies to most vehicles equipped with the OBD-II standard, including brands such as Toyota, Volkswagen, Ford, Dodge, Honda, Chevrolet, Hyundai, Audi, Acura, and many others.

At Nissan, for example, it is often labeled “Variable Camshaft Timing Control – Bank 2 – Performance”.

VVT/VCT System Operation and Causes of the Fault

Code P0021 is directly related to the Variable Valve Timing (VVT) or Variable Camshaft Timing (VCT) system. This technology optimizes engine power and efficiency by continuously adjusting the camshaft timing.

The PCM (Powertrain Control Module) constantly monitors the position of the “A” camshaft (usually the intake camshaft). Code P0021 is triggered when the PCM detects that the timing of this camshaft on Bank 2 of the engine is too advanced compared to the specified range. It is essentially the mirror of code P0011, which concerns Bank 1.

Symptoms of Code P0021

The appearance of this code is often accompanied by several noticeable symptoms:

• ⛽ Hard starting of the engine
• 🔁 Rough or poor idle
• ⚡ Stalling or loss of power during acceleration
• 📈 Decreased fuel efficiency (excessive fuel consumption)
• ⚠️ Illumination of the Check Engine Light (MIL)

Potential Causes of P0021 Fault

Several malfunctions can be the cause of a P0021 code:

• 🔧 Incorrect mechanical timing of the camshaft
• 🔌 Wiring problem (short circuit, open circuit) to the Bank 2 VVT solenoid
• 🛢️ Engine oil pressure or quality issue (level too low, degraded oil, clogged filter)
• ⚙️ Faulty VVT control solenoid (stuck in the open position)
• 🧩 VVT actuator failure (piston or phaser gear)

Diagnosis and Possible Solutions

As it is often the result of a mechanical or hydraulic failure, diagnosing code P0021 requires a methodical approach:

1. Check the engine oil level and quality: dirty oil or a low level is a common cause.
2. Visually inspect the wiring and connector of the Bank 2 VVT solenoid for any signs of wear or corrosion.
3. Test the VVT solenoid using a multimeter (resistance check) and by applying 12V power to ensure it activates correctly.
4. Check the oil pressure at the solenoid to confirm that sufficient oil is reaching it.
5. Check the mechanical timing of the timing belt/chain, which may be out of adjustment.

Important note: This guide is generic. For an accurate diagnosis, it is highly recommended to consult the specific procedures for your vehicle in a repair manual or to seek the assistance of a professional technician with an advanced scan tool.

Conclusion and Call to Action

Code P0021 indicates an advanced timing problem on engine Bank 2, often related to the VVT system. Although some basic checks can be performed by an experienced DIYer, the complexity of the system often makes expert intervention necessary for reliable diagnosis and repair.

Need help diagnosing or repairing a P0021 code on your vehicle? Consult a specialized garage or obtain a repair manual specific to your model for detailed instructions and to avoid any further damage.