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DTC - Diagnostic Trouble Codes information

P0028

Powertrain Codes

P0028 - SUBARU - Intake Valve Control Solenoid Circuit Range/Performance Bank 2

Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Dirty engine oil - Low engine oil level - Intake valve control solenoid circuit open or shorted - Intake valve control solenoid circuit poor electrical connection - Faulty intake valve control solenoid

When Detected

ECM monitors OCV stuck while cam signal is normally generating and Valve cleaning is not in progress.If the CAM Acutal Position is too high or low and Difference between Cam Actual Positionand Desired Position is higher than 20° ECM determines that a fault exists and the P0028 codes is set.

Description

The Continuously Variable Valve Timing (CVVT) system is installed to the chain sprocket of the intake camshaft. This system controls the intake camshaft to provide the optimal valve timing. The Engine Control Module (ECM) controls the Oil Control Valve(OCV), based on the signals output from mass air flow, throttle position and engine coolant temperature. The CVVT controller regulates the intake camshaft angle using oil pressure through the OCV. As result, the relative position between the camshaft and the crankshaft becomes optimal, and the engine torque improves, fuel economy improves, exhaust emissions decrease under overall driving conditions.