Lexus IS250 · Service Manual ENGINE

P0340

Diagnostic trouble codes

DESCRIPTION

The intake camshaft's Variable Valve Timing (VVT) sensor (G signal) consists of a magnet and MRE element.
The VVT camshaft drive gear has a sensor plate with 3 teeth on its outer circumference. When the gear rotates, changes occur in the air gaps between the sensor plate and pickup coil, which affects the magnet. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the gear rotation data to pulse signals, and uses the pulse signals to determine the camshaft angle, which it sends to the ECM. Then the ECM uses this data to control fuel injection time and injection timing.
The crankshaft angle sensor plate has 34 teeth. The pickup coil generates 34 signals for each engine revolution. Based the G signal and actual crankshaft angle, the ECM detects the normal crankshaft angle. Also, based on the NE signal, the ECM detects the engine speed.
DTC No.
 DTC Detection Condition
 Trouble Area
P0340
P0345
  1. Input voltage to ECM remains 0.3 V or less, or 4.7 V or higher for more than 5 seconds, when 2 more seconds have elapsed after turning engine switch on (IG)
    (1 trip detection logic)
  2. No VVT sensor signal to ECM during cranking
    (1 trip detection logic)
  1. Open or short in VVT sensor for intake camshaft circuit
  2. VVT sensor for intake camshaft
  3. Camshaft timing gear for intake camshaft
  4. Jumped tooth of timing chain for intake camshaft
  5. ECM
P0342
P0347
 Output voltage of VVT sensor 0.3 V or less for 5 seconds
(1 trip detection logic)
  1. Open or short in VVT sensor for intake camshaft circuit
  2. VVT sensor for intake camshaft
  3. Camshaft timing gear for intake camshaft
  4. Jumped tooth of timing chain for intake camshaft
  5. ECM
P0343
P0348
 Output voltage of VVT sensor 4.7 V or more for 5 seconds
(1 trip detection logic)
  1. Open or short in VVT sensor for intake camshaft circuit
  2. VVT sensor for intake camshaft
  3. Camshaft timing gear for intake camshaft
  4. Jumped tooth of timing chain for intake camshaft
  5. ECM

  1. A107148E08
    Reference: Inspection using an oscilloscope

    HINT:
    1. The correct waveform is shown.
    2. VV1+ and VV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal.

    Item
    		 Content
    Terminals
    		 NE+ - NE-
    VV1+ - VV1-
    VV2+ - VV2-
    Equipment Settings
    		 5 V/DIV.
    20 ms./DIV.
    Conditions
    		Cranking or idling

WIRING DIAGRAM

Refer to DTC P0335 (Click here).

INSPECTION PROCEDURE

HINT:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred (Click here).


1. CHECK ECM TERMINAL VOLTAGE

  1. A107709E12
    Inspect the ECM using an oscilloscope.

    1. While the engine is idling, check the waveform between the terminals of the ECM connector.

      Standard:
      Tester Connection
      		 Specified Condition
      VV1+ (E3-21) - VV1- (E3-20)
      		 Correct waveform shown
      VV2+ (E3-19) - VV2- (E3-18)
      		 Correct waveform shown
      NE+ (E3-32) - NE- (E3-31)
      		 Correct waveform shown



OK
REPLACE ECM
NG


2. CHECK HARNESS AND CONNECTOR (SENSOR POWER SOURCE)

  1. A107149E12
    Disconnect the E19 or E30 VVT sensor connector.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Connection
    		 Specified Condition
    VC (E19-3) - Body ground
    		 4.5 to 5.0 V
    VC (E30-3) - Body ground
    		 4.5 to 5.0 V

  1. Reconnect the VVT sensor connector.



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK HARNESS AND CONNECTOR (VVT SENSOR FOR INTAKE CAMSHAFT - ECM)

  1. A107710E12
    Disconnect the E19 or E30 VVT sensor connector.

  1. Disconnect the E3 ECM connector.

  1. Measure the resistance of the wire harness side connector.

    Standard resistance (Check for open):
    Tester Connection
    		 Specified Condition
    VVR+ (E19-1) - VV1+ (E3-21)
    		 Below 1 Ω
    VVR- (E19-2) - VV1- (E3-20)
    		 Below 1 Ω
    VVL+ (E30-1) - VV2+ (E3-19)
    		 Below 1 Ω
    VVL- (E30-2) - VV2- (E3-18)
    		 Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    VVR+ (E19-1) or VV1+ (E3-21) - Body ground
    		 10 kΩ or higher
    VVR- (E19-2) or VV1- (E3-20) - Body ground
    		 10 kΩ or higher
    VVL+ (E30-1) or VV2+ (E3-19) - Body ground
    		 10 kΩ or higher
    VVL- (E30-2) or VV2- (E3-18) - Body ground
    		 10 kΩ or higher

  1. Reconnect the VVT sensor connector.

  1. Reconnect the ECM connector.



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4. CHECK VVT SENSOR FOR INTAKE CAMSHAFT (SENSOR INSTALLATION)

  1. BR03795E17
    Check the CKP sensor installation.

    OK:
    Sensor is installed correctly.



 NG
REPAIR OR REPLACE VVT SENSOR
OK


5. CHECK CAMSHAFT TIMING GEAR ASSEMBLY (TEETH OF PLATE)

  1. Check the teeth of the signal plate.

OK:
Sensor plate teeth do not have any cracks or deformation.



 NG
REPLACE CAMSHAFT TIMING GEAR ASSEMBLY
OK

REPLACE VVT SENSOR


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