Lexus IS250 · Service Manual ENGINE

P0443

Diagnostic trouble codes

DESCRIPTION

To reduce HC emissions, evaporated fuel from the fuel tank is routed through the charcoal canister to the intake manifold for combustion in the cylinders.
The ECM changes the duty signal to the VSV for EVAP so that the intake quantity of HC emissions is appropriate for the driving conditions (engine load, engine speed, vehicle speed, etc.) after the engine is warmed up.
DTC NO.
 DTC Detection Condition
 Trouble Area
P0443
 Proper response to ECM command does not occur
(1 trip detection logic)
  1. Open or short in VSV for EVAP circuit
  2. VSV for EVAP
  3. ECM

WIRING DIAGRAM

A118551E04

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.


1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (VSV FOR EVAP)

  1. A080362E01
    Disconnect the vacuum hose from the VSV for EVAP.

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine and turn the tester ON.

  1. Enter the following menus: Power train / Engine / Active Test / Activate the VSV for EVAP Control. Press the right or left button.

  1. Check if air is sucked into the port when operating the VSV for EVAP using the intelligent tester.

    Standard:
    Tester Operation
    		 Specified Condition
    VSV is ON
    		 Air is sucked
    VSV is OFF
    		 No air sucked



OK
CHECK FOR INTERMITTENT PROBLEMS
NG


2. INSPECT ECM (CHECK VOLTAGE)

  1. A126135E08
    Turn the engine switch on (IG).

  1. Measure the voltage between the terminals or the E3 and E4 ECM connectors.

    Standard voltage:
    Tester Connection
    		 Specified Condition
    PRG (E3-11) - E1 (E4-7)
    		 9 to 14 V



OK
REPLACE ECM
NG


3. INSPECT DUTY VACUUM SWITCHING VALVE (OPERATION OF VSV FOR EVAP)


NG
REPLACE DUTY VACUUM SWITCHING VALVE
OK


4. CHECK HARNESS AND CONNECTOR (ECM - VSV FOR EVAP)

  1. A110585E05
    Disconnect the E3 ECM connector.

  1. Disconnect the E15 VSV for EVAP connector.

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

    Standard resistance (Check for open):
    Tester Connection
    		 Specified Condition
    VSV for EVAP (E15-2) - PRG (E3-11)
    		 Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    VSV for EVAP (E15-2) or PRG (E3-11) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5. CHECK HARNESS AND CONNECTOR (EFI NO. 2 FUSE - VSV FOR EVAP)

  1. A111072E02
    Remove the EFI NO. 2 fuse from the engine room No. 2 relay block and junction block.

  1. Disconnect the E15 VSV for EVAP connector.

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

    Standard resistance (Check for open):
    Tester Connection
    		 Specified Condition
    VSV for EVAP (E15-1) - EFI NO. 2 fuse (2)
    		 Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    VSV for EVAP (E15-1) or EFI NO. 2 fuse (2) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

INSPECT ECM POWER SOURCE CIRCUIT


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