Malfunction Indicator Lamp: Testing and Inspection

2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: MIL Circuit

MIL Circuit

DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunctions detected by the ECM. When the ignition switch is turned on (IG), 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 on (IG), 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 Techstream.

WIRING DIAGRAM









INSPECTION PROCEDURE

PROCEDURE

1. CHECK THAT MIL IS ILLUMINATED
(a) Turn the ignition switch on (IG).
(b) Check the illumination of the MIL.
Result:






B -- CHECK THAT ENGINE STARTS
A -- Continue to next step.
2. CHECK WHETHER MIL TURNS OFF
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch on (IG) and turn the tester on.
(c) Select the following menu items: Powertrain / Engine and ECT / Trouble Code.
(d) Check if any DTCs have been stored. Note down any DTCs.
(e) Clear the DTCs.
(f) Check if the MIL goes off.
Standard:
MIL goes off.
NG -- CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)
OK -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)





(a) Disconnect the ECM connector.
(b) Turn the ignition switch on (IG).
(c) Check that the MIL is not illuminated.
OK:
MIL is not illuminated.
(d) Reconnect the ECM connector.
NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)
OK -- REPLACE ECM
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)





(a) Disconnect the ECM connector.
(b) Disconnect the combination meter connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for Open):






Standard resistance (Check for Short):





(d) Reconnect the ECM connector.
(e) Reconnect the combination meter connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)
OK -- REPLACE COMBINATION METER ASSEMBLY
5. CHECK THAT ENGINE STARTS
(a) Turn the ignition switch on (IG).
(b) Start the engine.
Result:





HINT: *: The tester cannot communicate with the ECM.

B -- GO TO VC OUTPUT CIRCUIT
A -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (COMBINATION METER - BODY GROUND)





(a) Disconnect the ECM connector.
(b) Turn the ignition switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(d) Reconnect the ECM connector.
NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)
OK -- REPLACE ECM
7. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)





(a) Disconnect the ECM connector.
(b) Disconnect the combination meter connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for short):






Standard resistance (Check for Short):





(d) Reconnect the ECM connector.
(e) Reconnect the combination meter connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)
OK -- REPLACE COMBINATION METER ASSEMBLY