MIL Circuit: Procedure

WARNING: This page is about a different car, the 2009 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

CHECK MIL CONDITION (WHETHER MIL TURNS OFF)
1. Connect Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the tester on.
4. Check whether any DTCs have been stored. Refer to DTC CHECK / CLEAR . Note them down if necessary.
5. Clear DTCs. Refer to DTC CHECK / CLEAR .
6. Check if the MIL turns off.
  OK
  
  MIL turns off.
OK → REPAIR CIRCUIT INDICATED BY OUTPUT DTC

NG: Go to next step
CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the A6 ECM connector.
  
  Fig 1: Identifying A6 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the engine switch on (IG).
3. Check the MIL is not illuminated.
  OK
  
  MIL is not illuminated.
4. Reconnect the ECM connector.
OK → REPLACE ECM

NG: Go to next step

CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

Disconnect the A6 ECM connector.

Fig 2: Identifying Connectors
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Disconnect the J35 combination meter connector.

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

Standard resistance (Check for open)

Tester Connection	Specified Condition
W (A6-8) - EFI (J35-12)	Below 1 Ω

Standard resistance (Check for short)

Tester Connection	Specified Condition
W (A6-8) or EFI (J35-12) - Body ground	10 kΩ or higher

OK → REPAIR OR REPLACE COMBINATION METER ASSEMBLY

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK MIL (MIL IS ILLUMINATED)
1. Check if the MIL is illuminated when the engine switch is turns on (IG).
  OK
  
  MIL is illuminated.
OK → SYSTEM IS OK

NG: Go to next step

CHECK HARNESS AND CONNECTOR

Disconnect the A6 ECM connector.

Fig 3: Identifying A6 ECM Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Turn the engine switch on (IG).

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

Standard voltage

Tester Connection	Specified Condition
W (A6-8) - Body ground	10 to 14 V

Reconnect the ECM connector.

OK → REPLACE ECM

NG: Go to next step