VC Output Circuit

2UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: VC Output Circuit

VC Output Circuit

DESCRIPTION

The ECM constantly uses 5 V from the battery voltage 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 short-circuited, the microprocessor in the ECM and sensors that are supplied with 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
HINT: When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.

PROCEDURE

1. CHECK MIL
(a) Check that the Malfunction Indicator Lamp (MIL) lights up when turning the power switch ON (IG).
OK:
MIL lights up.
NG -- CHECK CONNECTION BETWEEN TECHSTREAM AND ECM
OK -- SYSTEM OK
2. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch ON (IG) and Techstream ON.
(c) Check the communication between the Techstream and ECM.

Result





A -- GO TO MIL CIRCUIT
B -- Continue to next step.
3. CHECK MIL (THROTTLE BODY)
(a) Disconnect the throttle body connector.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE THROTTLE BODY ASSEMBLY
B -- Continue to next step.
4. CHECK MIL (FUEL TANK PRESSURE SENSOR)
(a) Disconnect the fuel tank pressure sensor connector.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE FUEL TANK PRESSURE SENSOR
B -- Continue to next step.
5. CHECK MIL (CANISTER PUMP MODULE)
(a) Disconnect the canister pump module connector.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE CANISTER ASSEMBLY
B -- Continue to next step.
6. CHECK MIL (CRANKSHAFT POSITION SENSOR)
(a) Disconnect the crankshaft position sensor.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE CRANKSHAFT POSITION SENSOR
B -- Continue to next step.
7. CHECK MIL (CAMSHAFT POSITION SENSOR)
(a) Disconnect the camshaft position sensor.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE CAMSHAFT POSITION SENSOR
B -- Continue to next step.
8. CHECK MIL (VVT SENSOR FOR INTAKE SIDE OF BANK 1)
(a) Remove the air cleaner assembly LH Removal.
(b) Disconnect the VVT sensor for intake side of bank 1 connector.
(c) Turn the power switch ON (IG).
(d) Check the MIL.

Result





A -- REPLACE VVT SENSOR FOR INTAKE SIDE OF BANK 1
B -- Continue to next step.
9. CHECK MIL (VVT SENSOR FOR EXHAUST SIDE OF BANK 1)
(a) Disconnect the VVT sensor for exhaust side of bank 1 connector.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE VVT SENSOR FOR EXHAUST SIDE OF BANK 1
B -- Continue to next step.
10. CHECK MIL (VVT SENSOR FOR INTAKE SIDE OF BANK 2)
(a) Remove the air cleaner assembly RH Removal.
(b) Disconnect the VVT sensor for intake side of bank 2 connector.
(c) Turn the power switch ON (IG).
(d) Check the MIL.

Result





A -- REPLACE VVT SENSOR FOR INTAKE SIDE OF BANK 2
B -- Continue to next step.
11. CHECK MIL (VVT SENSOR FOR EXHAUST SIDE OF BANK 2)
(a) Disconnect the VVT sensor for exhaust side of bank 2 connector.
(b) Turn the power switch ON (IG).
(c) Check the MIL.

Result





A -- REPLACE VVT SENSOR FOR EXHAUST SIDE OF BANK 2
B -- Continue to next step.
12. CHECK MIL (FUEL PRESSURE SENSOR)
(a) Remove the intake manifold Removal.
(b) Disconnect the fuel pressure sensor connector.
(c) Turn the power switch ON (IG).
(d) Check the MIL.

Result





A -- REPLACE FUEL PRESSURE SENSOR
B -- Continue to next step.
13.
CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)




(a) Disconnect the throttle body connector.
(b) Disconnect the fuel tank pressure sensor connector.
(c) Disconnect the canister pump module connector.
(d) Disconnect the VVT sensor (for intake side of bank 1).
(e) Disconnect the VVT sensor (for exhaust side of bank 1).
(f) Disconnect the VVT sensor (for intake side of bank 2).
(g) Disconnect the VVT sensor (for exhaust side of bank 2).
(h) Disconnect the crankshaft position sensor.
(i) Disconnect the camshaft position sensor.
(j) Disconnect the fuel pressure sensor.
(k) Disconnect the E1 and E2 ECM connectors.
(l) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for short):






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM