SFI SYSTEM VC Output Circuit

DESCRIPTION

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

When the VC circuit is short-circuited, the microprocessor in the ECM and the sensors that are supplied with power through the VC circuit are inactivated because 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.

WIRING DIAGRAM

PROCEDURE

1. CHECK MIL

   
   

   1. Check that the Malfunction Indicator Lamp (MIL) lights up when the ignition switch is turned to ON (IG).

      OK
      MIL lights up.

   
   

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   NG

2. CHECK COMMUNICATION BETWEEN GTS AND ECM

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the ignition switch to ON (IG).

   3. Turn the GTS on.

   4. Check the communication between the GTS and ECM.

      Result

      Result	Proceed to
      Communication is not possible	A
      Communication is possible	B

   
   

   B

   GO TO MIL CIRCUIT Click here

   A

3. CHECK MIL (THROTTLE POSITION SENSOR)

   
   

   1. Disconnect the throttle body with motor assembly connector.

   2. Turn the ignition switch to ON (IG).

   3. Check the MIL.

      Result

      Result	Proceed to
      MIL does not illuminate	A
      MIL illuminates	B

      Tech Tips

      Perform "Inspection After Repair" after replacing the throttle body with motor assembly Click here.

   
   

   B

   REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY Click here

   A

4. CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)

   
   

   1. Disconnect the manifold absolute pressure sensor connector.

   2. Turn the ignition switch to ON (IG).

   3. Check the MIL.

      Result

      Result	Proceed to
      MIL does not illuminate	A
      MIL illuminates	B

   
   

   B

   REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

   A

5. CHECK HARNESS AND CONNECTOR

   
   

   1. Disconnect the C12 throttle body with motor assembly connector.

   2. Disconnect the C15 manifold absolute pressure sensor connector.

   3. Disconnect the C10 ECM connector (for LHD).

   4. Disconnect the C9 ECM connector (for RHD).

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

      Standard Resistance
      for LHD Tester Connection Condition Specified Condition C10-115 (VCTA) - Body ground Always 10 kΩ or higher C10-118 (VCPM) - Body ground Always 10 kΩ or higher
      for RHD Tester Connection Condition Specified Condition C9-115 (VCTA) - Body ground Always 10 kΩ or higher C9-118 (VCPM) - Body ground Always 10 kΩ or higher

   
   

   OK

   REPLACE ECM Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR