VC Output Circuit
2AR-FXE ENGINE CONTROL: SFI SYSTEM: VC Output Circuit
- 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.
HINT
Under normal conditions, the MIL is illuminated when the power switch is first turned on (IG). The MIL goes off when the power switch on (READY).
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. CHECK MIL
(a) Check that the Malfunction Indicator Lamp (MIL) lights up when the power switch is turned on (IG).
OK:
MIL lights up.
NG -- CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM
OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures
2. CHECK COMMUNICATION 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 MIL Circuit
A -- Continue to next step.
3. CHECK MIL (THROTTLE POSITION SENSOR)
(a) Disconnect the throttle with motor body assembly connector.
(b) Turn the power switch on (IG).
(c) Check the MIL.
Result
HINT
Perform "Inspection After Repair" after replacing the throttle with motor body assembly Programming and Relearning.
B -- REPLACE THROTTLE WITH MOTOR 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 PUMP MODULE Removal
A -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR
(a) Disconnect the throttle with motor body assembly 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 connectors.
(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