P0012
DTC P0012 CAMSHAFT POSITION "A" -TIMING OVER-RETARDED (BANK 1)CIRCUIT DESCRIPTION
DTC Detection Condition:
The Variable Valve Timing (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, sent to the OCV, regulates the oil pressure applied to the VVT controller. Camshaft timing control is performed based on engine operation conditions such as intake air volume, throttle position and engine coolant temperature.
The ECM controls the OCV based on the signals output from several 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 is optimized. Also, the engine torque and fuel economy improve, and exhaust emissions decrease. The ECM detects the actual valve timing using signals from the camshaft position sensor and the crankshaft position sensor. The ECM performs feedback control and verifies target valve timing.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
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, sent to the OCV, regulates the oil pressure applied to the VVT controller. The VVT controller can advance or retard the intake valve camshaft.
Example:
A DTC will be set if: 1) the difference between the "target" and "actual" valve timing is more than 5 degrees of the camshaft 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.
TYPICAL MALFUNCTION THRESHOLDS
Typical Malfunction Thresholds:
If the difference between "target" and "actual" camshaft timing is larger than the specified value, the ECM operates the VVT actuator.
The ECM then monitors the camshaft timing change for 5 seconds.
Wiring Diagram:
INSPECTION PROCEDURE
HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. 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.
Step 1 - 2:
Step 3 - 4:
Step 5 - 10:
Step 11:
Hand-held tester:
Step 1 - 2:
Step 3 - 4:
Step 5 - 10:
Step 11:
OBD II scan tool (excluding hand-held tester):
CHECK FOR INTERMITTENT PROBLEMS
Hand held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode with the hand held tester. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.
a. Clear the DTCs.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and the connector.