P0021

DTC P0021 CAMSHAFT POSITION "A" - TIMING OVER - ADVANCED OR SYSTEM PERFORMANCE (BANK 2)

HINT:
- If DTC P0011 or P0012 is displayed, check the bank 1 VVT system circuit.
- If DTC P0021 or P0022 is displayed, check the bank 2 VVT system circuit.
- Bank 1 includes cylinder No. 1, but bank 2 does not. Cylinder No. 1 is located in the front part of the engine, opposite the transmission.

CIRCUIT DESCRIPTION

DTC Detection Condition:

The Variable Valve Timing (VVT) system controls the intake camshaft to provide the optimal valve timing for every driving condition. This control is performed based on the signals, such conditions as intake air volume, throttle position and engine coolant temperature.

The ECM controls the oil control valve (OCV), based on the signals output from the sensors. The VVT controller regulates the intake camshaft angle using oil pressure through the OCV. As a result, the relative position between the camshaft and the crankshaft becomes optimal, the engine torque and fuel economy improves, and then the exhaust emissions decrease under overall driving conditions. Also, the ECM detects the actual valve timing using the signals from the camshaft position sensor and the crankshaft position sensor, and performs feedback control. This is how target valve timing is achieved by the ECM.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

The ECM optimizes the valve timing using the Variable Valve Timing (VVT) system to control the intake valve camshaft. The VVT system includes the ECM, the Oil Control Valve (OCV) and the VVT controller. The ECM sends a target "duty-cycle" control signal to the OCV. This control signal, applied to the OCV, regulates the oil pressure supplied to the VVT controller. The VVT controller can advance or retard the intake valve camshaft.

Example: A DTC will set if: 1.the difference between the target and actual valve timing is more than 5 degrees of the crankshaft angle (CA) and the condition continues for more than 4.5 seconds; or 2.the OCV is forcibly activated 63 times or more.

Advanced cam DTCs are subject to "1 trip" detection logic.
Retarded cam DTCs are subject to "2 trip" detection logic.

If the difference between target and actual camshaft timing is larger than the specified value, the ECM operates the VVT actuator. Then, the ECM monitors the camshaft timing change for 5 seconds.

Wiring Diagram:

Step 1 - 2:

Step 3 - 4:

Step 5:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when a malfunction is detected.When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.

NOTE: DTCs P0011, P0012, P0021 or P0022 is output when a foreign object in the engine oil enters the system. These codes are stored even if the system returns to normal after a short time.Foreign objects are filtered out by the oil filter.

NOTE: After replacing the camshaft timing gear, check the DTC.

a. Clear the DTC and select the check mode
b. Start and warm up the engine.
c. Drive the vehicle for 10 minutes or more.
d. Check that no DTC is output.