Brand:

Toyota

Model Name:

Yaris NCP90 91 92 93

Manual:

Repair Manual

Section:

1Nz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Wiring diagram

  3. Inspection procedure

  4. Check that mil is illuminated

  5. Check whether mil turns off

  6. Check harness and connector (check for short in wire harness)

  7. Check harness and connector (combination meter - ecm)

  8. Check that mil is illuminated

  9. Check that engine starts

  10. Inspect combination meter assembly (mil circuit)

SFI SYSTEM > MIL Circuit


​

DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM. When the ignition switch is turned to ON, power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.
The MIL operation can be checked visually: When the ignition switch is first turned to ON, the MIL should be illuminated and should then turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using an intelligent tester.

WIRING DIAGRAM


Perform troubleshooting in accordance with the table below.ConditionsProceed ToMIL remains ONAMIL does not illuminateB Yaris


INSPECTION PROCEDURE

1.CHECK THAT MIL IS ILLUMINATED

  1. Perform troubleshooting in accordance with the table below.

    Conditions
    		Proceed To
    MIL remains ON
    		A
    MIL does not illuminate
    		B


Bnext
Go to step 5
A
next down

2.CHECK WHETHER MIL TURNS OFF

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / DTC.

  1. Check if any DTCs have been stored. Note down any DTCs.

  1. Clear DTCs (Click here).

  1. Check if the MIL goes off.

    Standard:
    MIL should go off.


OKnext
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
NG
next down

3.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)
Disconnect the A21 ECM connector. Yaris

  1. Disconnect the A21 ECM connector.

  1. Turn the ignition switch to ON.

  1. Check that the MIL is not illuminated.

    OK:
    MIL is not illuminated.

  1. Reconnect the ECM connector.



OKnext
REPLACE ECM (Click here)
NG
next down

4.CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)
Disconnect the A21 ECM connector. Yaris

  1. Disconnect the A21 ECM connector.

  1. Disconnect the D2 combination meter connector (for Hatchback).

  1. Disconnect the D84 combination meter connector (for Sedan).

  1. Check the resistance.

    Standard resistance (Check for short):
    Tester Connections
    		Specified Conditions
    W (A21-24) or combination meter (D2-4) or (D2-5) - Body ground
    		10 kΩ or higher
    W (A21-24) or combination meter (D84-4) - Body ground

  1. Reconnect the ECM connector.

  1. Reconnect the combination meter connector.



OKnext
REPAIR OR REPLACE COMBINATION METER ASSEMBLY
NG
next down
REPAIR OR REPLACE HARNESS OR CONNECTOR

5.CHECK THAT MIL IS ILLUMINATED

  1. Check if the MIL is illuminated when the ignition switch is turned to ON.

    OK:
    MIL should be illuminated.


OKnext
SYSTEM OK
NG
next down

6.CHECK THAT ENGINE STARTS

  1. Turn the ignition switch to ON.

  1. Start the engine.

    Result:
    Result
    		Proceed To
    Engine starts
    		A
    Engine does not start*
    		B
    HINT:
    *: The intelligent tester cannot communicate with the ECM.


Bnext
GO TO VC OUTPUT CIRCUIT (Click here)
A
next down

7.INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)
  1. Check the MIL circuit for Hatchback (Click here).
  2. Check the MIL circuit for Sedan (Click here).


NGnext
REPAIR OR REPLACE COMBINATION METER ASSEMBLY
OK
next down
CHECK AND REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)