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Code P0021

Symptoms

• Check Engine Light is on

• Rough engine idle

• Reduced engine performance

Common Causes

• Faulty camshaft position sensor

• Timing chain or belt issues

• Problems with the Variable Valve Timing (VVT) solenoid

Glossary

Camshaft: A shaft in the engine that controls the opening and closing of the valves.

VVT: Variable Valve Timing, a system that adjusts the timing of the camshaft for better performance.

Related Codes

• P0011

• P0022

Official description

A Camshaft Position - Timing Over-Advanced or System Performance Bank 2

Laymans terms

Your car's engine has a part called a camshaft that helps it run smoothly. This code means that the camshaft on one side of the engine is not in the right position, and it's moving too far ahead of where it should be.

Explanation

The engine's camshaft timing is advanced beyond the expected range, affecting engine performance.

Technical description

The P0021 code indicates that the Engine Control Module (ECM) has detected the camshaft timing for bank 2 is over-advanced. This can occur due to issues with the Variable Valve Timing (VVT) system, which adjusts the camshaft position to optimize engine performance.

Diagnosis steps

• Use an OBD-II scanner to confirm the code.

• Inspect the camshaft position sensor and wiring.

• Check the VVT solenoid for proper operation.

Repair procedures

• Replace the camshaft position sensor if faulty.

• Repair or replace the timing chain or belt if needed.

• Clean or replace the VVT solenoid.

Tools required

• OBD-II scanner

• Multimeter

• Wrench set

Estimated repair cost

$200 - $600

Difficulty level

Moderate

Commonly affected vehicles

• Nissan Altima

• Infiniti G35

• Subaru Outback

Preventive measures

• Regularly change engine oil and filter.

• Inspect timing components periodically.

• Use high-quality oil to prevent sludge.

Error code type

Engine Performance

User experience recommendations

• Avoid driving the vehicle until repaired to prevent further damage.

• Consult a professional mechanic for accurate diagnosis.

Warranty information

Check if your vehicle is still under powertrain warranty, which may cover this repair.

Historical data

The P0021 code has been commonly reported in vehicles with high mileage or poor maintenance history.

Urgency level

Moderate – Should be addressed soon to prevent potential engine damage.

Legal and safety notice

Driving with this code can lead to increased emissions and potential engine damage.

Testing conditions

• Engine at operating temperature

• Vehicle in idle and various RPM ranges

Component location

The camshaft position sensor and VVT solenoid are typically located near the top of the engine, on the cylinder head of bank 2.

FAQs

Q: Can I drive my car with a P0021 code?
A: It's not recommended to drive with this code as it can lead to engine damage.

Q: How can I prevent a P0021 code?
A: Regular maintenance, including timely oil changes and inspections, can help prevent this code.

Last updated: Mar 1, 2026 • Source: internal database
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