VC Output Circuit

2ZR-FXE ENGINE CONTROL: SFI SYSTEM: VC Output Circuit
- VC Output Circuit

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.





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





INSPECTION PROCEDURE

PROCEDURE

1. CHECK MIL

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

OK:

MIL lights up.

NG -- CHECK CONNECTION BETWEEN TECHSTREAM AND ECM

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

2. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Check the communication between the Techstream and ECM.

Result





B -- GO TO MIL CIRCUIT Testing and Inspection
A -- Continue to next step.

3. CHECK MIL (THROTTLE POSITION SENSOR)

(a) Disconnect the throttle position sensor connector.

(b) Turn the power switch on (IG).

(c) Check the MIL.

Result





B -- REPLACE THROTTLE BODY ASSEMBLY Removal
A -- Continue to next step.

4. CHECK MIL (CAMSHAFT POSITION SENSOR)

(a) Disconnect the camshaft position sensor connector.

(b) Turn the power switch on (IG).

(c) Check the MIL.

Result





B -- REPLACE CAMSHAFT POSITION SENSOR Removal
A -- Continue to next step.

5. CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)

(a) Disconnect the manifold absolute pressure sensor connector.

(b) Turn the power switch on (IG).

(c) Check the MIL.

Result





B -- REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Removal
A -- Continue to next step.

6. CHECK MIL (CANISTER PUMP MODULE)

(a) Disconnect the canister pump module connector.

(b) Turn the power switch on (IG).

(c) Check the MIL.

Result





B -- REPLACE CANISTER ASSEMBLY Removal
A -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

(a) Disconnect the throttle position sensor connector.

(b) Disconnect the camshaft position sensor connector.

(c) Disconnect the manifold absolute pressure sensor connector.

(d) Disconnect the canister pump module connector.

(e) Disconnect the ECM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal