P0021

DTC P0011 Camshaft Position "A" - Timing Over-Advanced or System Performance (Bank 1)
DTC P0012 Camshaft Position "A" - Timing Over-Retarded (Bank 1)
DTC P0021 Camshaft Position "A" - Timing Over-Advanced or System Performance (Bank 2)
DTC P0022 Camshaft Position "A" - Timing Over-Retarded ES (Bank 2)

DESCRIPTION

DTC Detection Condition:

The Variable Valve Timing (VVT) system includes the ECM, Oil Control Valve (OCV) and VVT controller. The ECM sends a target duty-cycle control signal to the OCV. This control signal regulates the oil pressure supplied to the VVT controller. Camshaft timing control is performed according to engine operating conditions such as intake air volume, throttle valve position and engine coolant temperature. The ECM controls the OCV, based on the signals transmitted by several sensors. The VVT controller regulates the intake camshaft angle using oil pressure through the OCV. As a result, the relative positions of the camshaft and crankshaft are optimized, the engine torque and fuel economy improve, and the exhaust emissions decrease under overall driving conditions. The ECM detects the actual intake valve timing using signals from the camshaft and crankshaft position sensors, and performs feedback control. This is how the target intake valve timing is verified by the ECM.

HINT:
- Refer to DTC P0011, P0012, P0021 and P0022 is present, check the Variable Valve Timing (VVT) system.
- Refer to DTC P0010

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 OCV and the VVT actuator. 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 ° 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.

The monitor runs if all the conditions are met:
- After engine warm-up (engine coolant temperature is 75 °C (167 °F) or more.
- After driving the vehicle over 40 km/h (25 mph) for 3 minutes.
- After idling the engine for 3 minutes.

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 2(Continued)-4:

Step 5-7:

INSPECTION PROCEDURE

HINT:
- If DTC P0011 or P0012 is displayed, check the bank 1 Variable Valve Timing (VVT) system circuit.
- If DTC P0021 or P0022 is displayed, check the bank 2 VVT system circuit.
- Bank 1 includes No. 1 cylinder, but bank 2 does not. No. 1 cylinder is located in the front part of the engine, opposite the transmission.
- Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are 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: DTC P0011, P0012, P0021 or P0022 is also output when a foreign object is detected in some parts of the system in the engine oil, and then the system returns to normal in a short time. As the ECM is controlled to eject a foreign object, there is no problem with the VVT. There is also no problem with the VVT as the oil filter should catch the foreign object in the engine oil.