| CAUTION | If Engine Control Module (ECM) replacement is instructed in following test, always ensure ECM electrical connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. On models equipped with engine immobilizer, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Circuit Description
The Variable Valve Timing (VVT) sensor is a pick-up coil located on end of cylinder head at flywheel end of engine and uses a signal plate on outer circumference of intake camshaft. VVT sensor may also be referred to as camshaft position sensor. The ECM uses input signal from VVT sensor to determine the standard crankshaft angle for controlling the intake valve timing. DTC is set when ECM detects a deviation in crankshaft position sensor and VVT sensor signals. Possible causes are
- Mechanical system malfunction such as the timing chain stretched or jumped teeth.
- 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.