| CAUTION | If ECM replacement is instructed in following tests, always ensure ECM connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
The Variable Valve Timing (VVT) system controls intake valve timing in response to driving conditions. ECM controls Variable Valve Timing (VVT) Oil Control Valve (OCV) to ensure correct valve timing. VVT OCV is located on timing chain side of cylinder head, next to intake manifold. Oil pressure controlled by VVT OCV is supplied to VVT controller. VVT controller then changes relative position between camshaft and crankshaft. VVT controller is located on front of intake camshaft. DTC P1349 is set if ECM detects valve timing does not change (fixed timing). Possible causes are
- Incorrect valve timing.
- Defective VVT OCV.
- Defective VVT controller assembly.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.