VC Output Circuit 2ZR-FXE

VC Output Circuit

Description

Wiring diagram

Inspection procedure

Check MIL

Check connection between intelligent tester and ECM

Check mil (throttle position sensor)

Check mil (camshaft position sensor)

Check mil (manifold absolute pressure sensor)

Check harness and connector

Description

The ECM constantly uses 5 V from the auxiliary battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

Lexus VC Output Circuit. Description.

When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.

HINT:

Under normal conditions, the MIL is illuminated for several seconds when the power switch is first turned on (IG). The MIL goes off when the engine is started.

Wiring diagram

Lexus VC Output Circuit. Wiring diagram

Inspection procedure

1.CHECK MIL

  1. Check that the Malfunction Indicator Lamp (MIL) illuminates when turning the power switch on (IG).

    OK:

    MIL lights up.

  NG  
Go to step 2
 
OK  
   
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Check the communication between the intelligent tester and ECM.

    Result
    Result Proceed to
    Communication is not possible A
    Communication is possible B
  B  
GO TO MIL CIRCUIT
 
OK  
   

3.CHECK MIL (THROTTLE POSITION SENSOR)

  1. Disconnect the throttle position sensor connector.

  1. Turn the power switch on (IG).

  1. Check the MIL.

    Result
    Result Proceed to
    MIL does not illuminate A
    MIL illuminates B
  B  
REPLACE THROTTLE BODY ASSEMBLY
 
OK  
   

4.CHECK MIL (CAMSHAFT POSITION SENSOR)

  1. Disconnect the camshaft position sensor connector.

  1. Turn the power switch on (IG).

  1. Check the MIL.

    Result
    Result Proceed to
    MIL does not illuminate A
    MIL illuminates B
  B  
REPLACE CAMSHAFT POSITION SENSOR
 
OK  
   

5.CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)

  1. Disconnect the manifold absolute pressure sensor connector.

  1. Turn the power switch on (IG).

  1. Check the MIL.

    Result
    Result Proceed to
    MIL does not illuminate A
    MIL illuminates B
  B  
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
 
OK  
   

6.CHECK HARNESS AND CONNECTOR

  1. Disconnect the throttle position sensor connector.

  1. Disconnect the camshaft position sensor connector.

  1. Disconnect the manifold absolute pressure sensor connector.

  1. Disconnect the ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:

    Tester Connection Condition Specified Condition
    D4-5 (VC) or D27-88 (VCTA) - Body ground Always 10 k? or higher
    D18-3 (VC) or D27-99 (VCV1) - Body ground Always 10 k? or higher
    D3-3 (VC) or D27-72 (VCPM) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
REPLACE ECM