P0012

2AZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: DTC P0012 - Camshaft Position "A" - Timing Over-Retarded (Bank 1)

DESCRIPTION

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.





HINT: If DTC P0011 or P0012 is present, check the VVT (Variable Valve Timing) system.





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 is set when the following conditions 1, 2 and 3 are met:
1. The difference between the target and actual intake valve timing is more than 5°CA (Crankshaft Angle) and the condition continues for more than 4.5 seconds.
2. It takes 5 seconds or more to change the valve timing by 5°CA.
3. After above conditions 1 and 2 are met, the camshaft timing oil control valve assembly is forcibly activated during 10 seconds.
DTC P0011 (Advanced Cam Timing) is subject to 1 trip detection logic.
DTC P0012 (Retarded Cam Timing) is subject to 2 trip detection logic.
These DTCs indicate that the VVT controller cannot operate properly due to camshaft timing oil control valve assembly malfunctions or the presence of foreign objects in the camshaft timing oil control valve.
The monitor will run if all of the following conditions are met:

- The engine is warm (the engine coolant temperature is 75°C [167°F] or more).
- The vehicle has been driven at more than 40 mph (64 km/h) for 3 minutes.
- The engine has idled for 3 minutes.

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
NOTICE: 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 Techstream. 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 Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and turn the Techstream on.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble 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 Techstream to the DLC3.
(b) Start the engine and turn the Techstream on.
(c) Warm up the engine.
(d) On the Techstream, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1).
(e) Check the engine speed while operating the Oil Control Valve (OCV) using the Techstream.
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 Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and turn the Techstream 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 Techstream Check Mode Procedure.
(f) Drive the vehicle for more than 10 minutes.
(g) Read the DTCs using the Techstream.
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.
(d) Reinstall the cylinder head cover.
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.
(d) Reinstall the OCV.
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.
(d) Reinstall the generator.
(e) Reinstall the OCV filter.
NG -- CLEAN OIL CONTROL VALVE FILTER
OK -- Continue to next step.
7. REPLACE CAMSHAFT TIMING GEAR ASSEMBLY
(a) Replace the camshaft timing gear assembly.
NEXT -- Continue to next step.
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P0011, P0012)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and turn the Techstream 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 Techstream Check Mode Procedure.
(f) Drive the vehicle for more than 10 minutes.
(g) Select the following menus: Powertrain / Engine and ECT / Trouble Codes.
(h) Read DTCs.
Result:





B -- REPLACE ECM
A -- END