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DTC P1346: VARIABLE VALVE TIMING SENSOR CIRCUIT RANGE/PERFORMANCE Toyota Echo I

CAUTIONIf 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.

Note. Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor.

Circuit Description

The Variable Valve Timing (VVT) sensor consists of a signal plate and pick-up coil. The signal plate has one tooth and is mounted on each intake camshaft. The VVT sensor provides feedback to ECM in order to control intake valve timing. DTC is set when ECM detects a deviation in crankshaft position sensor and VVT sensor. Possible causes are

  1. Mechanical system malfunction such as the timing chain stretched or jumped teeth.
  2. 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.