P0012
DTC P0012 - Camshaft Position "A" - Timing Over-Retarded (Bank 1)
DESCRIPTION
HINT: If DTC P0011 or P0012 is present, check the VVT (Variable Valve Timing) system.
The Variable Valve Timing (VVT) system includes the ECM, 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 the 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.
MONITOR DESCRIPTION
The ECM optimizes the valve timing using the VVT (Variable Valve Timing) system to control the intake 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 regulates the oil pressure supplied to the VVT controller. The VVT controller can advance or retard the intake camshaft.
If the difference between the target and actual intake valve timings is large, and changes in actual intake valve timing are small, the ECM interprets this as the VVT controller stuck malfunction and sets a DTC.
Example:
A DTC will be set if 1) the difference between the target and actual valve timings is more than 5° of the camshaft angle (CA) and the condition continues for more than 4.5 seconds; or 2) the OCV is forcibly activated 12 times or more.
Advanced cam DTC is subject to "1 trip" detection logic.
Retarded cam DTC is subject to "2 trip" detection logic.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
Advanced camshaft timing:
Retarded camshaft timing:
If the difference between the target and actual camshaft timings is greater than the specified value, the ECM operates the VVT actuator.
Then, the ECM monitors the camshaft timing change for 5 seconds.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTE: DTC P0011 or P0012 may be set when foreign objects in the engine oil are caught in some parts of the system. The DTC will remain set even if the system returns to normal after a short time. Foreign objects are filtered out by the oil filter.
HINT: Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0011 OR P0012)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(d) Read the DTCs.
Result:
HINT: If any DTCs other than P0011 or P0012 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART
A -- Continue to next step.
2. PERFORM ACTIVE TEST (OPERATE OCV)
(a) Connect the intelligent tester to the DLC3.
(b) Start the engine and turn the tester on.
(c) Warm up the engine.
(d) On the tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / VVT B1.
(e) Check the engine speed while operating the Oil Control Valve (OCV) using the tester.
OK:
NG -- CHECK VALVE TIMING (CHECK FOR LOOSE AND JUMPED TEETH ON TIMING CHAIN)
OK -- Continue to next step.
3. CHECK WHETHER DTC OUTPUT RECURS (DTC P0011 OR P0012)
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Start the engine and warm it up.
(e) Switch the ECM from normal mode to check mode using the tester Check Mode Procedure.
(f) Drive the vehicle for more than 10 minutes.
(g) Read the DTCs using the tester.
OK:
No DTC output.
NG -- CHECK VALVE TIMING (CHECK FOR LOOSE AND JUMPED TEETH ON TIMING CHAIN)
OK -- END
4. CHECK VALVE TIMING (CHECK FOR LOOSE AND JUMPED TEETH ON TIMING CHAIN)
(a) Remove the cylinder head cover Disassembly.
(b) Turn the crankshaft pulley until its groove and the timing mark "0" of the timing chain cover are aligned.
(c) Check that each timing mark of the camshaft timing gears is aligned with its corresponding timing mark located on the No. 1 and No. 2 bearing caps as shown in the illustration.
If not, turn the crankshaft by 1 revolution (360°) to align the timing marks as above.
OK:
The timing marks of the camshaft timing gears are aligned with the timing marks located on the No. 1 and No. 2 bearing caps.
NG -- ADJUST VALVE TIMING
OK -- Continue to next step.
5. INSPECT CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY (OCV)
(a) Remove the OCV.
(b) Measure the resistance between the terminals of the OCV.
Standard resistance:
6.9 to 7.9 Ohms at 20°C (68°F)
(c) Apply the positive battery voltage to terminal 1 and negative battery voltage to terminal 2. Check the valve operation.
OK:
The valve moves quickly.
NG -- REPLACE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY
OK -- Continue to next step.
6. INSPECT OIL CONTROL VALVE FILTER
(a) Remove the generator Removal.
(b) Remove the OCV filter.
(c) Check that the filter is not clogged.
OK:
The filter is not clogged.
NG -- CLEAN OIL CONTROL VALVE FILTER
OK -- Continue to next step.
7. REPLACE CAMSHAFT TIMING GEAR ASSEMBLY
After replacing the camshaft timing gear, confirm that the DTC output does not recur.
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Start the engine and warm it up.
(e) Switch the ECM from normal mode to check mode using the tester Check Mode Procedure.
(f) Drive the vehicle for more than 10 minutes.
(g) Confirm that no DTC is set using the tester.
NEXT -- END