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DTC P1346/P1351: VARIABLE VALVE TIMING (VVT) Lexus LS III

CAUTIONIf ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. 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.

Circuit Description

The Variable Valve Timing (VVT) sensor is a camshaft position sensor mounted at center of each cylinder head, underneath intake manifold. VVT sensor consists of a signal plate and pick-up coil. Signal plate has one tooth and is mounted on intake camshafts. VVT sensor provides feedback to ECM in order to control intake valve timing. DTC P1346 is set when a deviation exists in Crankshaft Position (CKP) sensor and VVT bank No. 1 sensor. DTC P1351 is set when a deviation exists in CKP sensor and VVT bank No. 2 sensor. Possible causes are

  1. Mechanical system malfunction (timing belt stretched or timing belt teeth jumped).
  2. Faulty ECM.

Diagnostic Aids

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.