Code Definition

P0021 — Intake Variable Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0021

P0021 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0021 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; and a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0021 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC P0021 sets when the Engine Control Module detects that the bank 2 intake ('A') camshaft is timed further advanced than the position it is commanding through the variable valve timing system. The intake cam phaser is moved by engine oil that the ECM meters with an oil control solenoid (OCV), and the ECM compares the actual cam angle from the camshaft position sensor against its target; a persistent over advanced reading, or one the system cannot correct, triggers this performance code. Unlike the P0020 circuit code, P0021 is a rationality or mechanical fault, meaning the electrical circuit ...

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