LO-beam Headlight does not Illuminate: Procedure

1. Using the Techstream, read the Data List.
   MAIN BODY
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Head Light SW (Head)	Headlight dimmer switch (Head) signal/ON or OFF	ON: Headlight dimmer switch (Head) on OFF: Headlight dimmer switch off	-

   OK

   When the headlight dimmer switch operation is performed, the result will be the same as above.

NG → See step   3 

OK: Go to next step 

1. Using the Techstream, perform the Active Test.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Headlight Relay	Headlight	OFF/ON	-

   OK

   Headlight low beam turns on/off.

NG → See step   5 

OK → REPLACE MAIN BODY ECU 

1. Remove the headlight dimmer switch. Refer to INSPECTION .
   Fig 1: Inspecting Headlight Dimmer Switch

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   18 (T) - 12 (EL)	Headlight dimmer switch (Light control switch) head	Below 1 Ω
   18 (T) - 12 (EL)	Headlight dimmer switch (Light control switch) off	10 kΩ or higher

NG → See step   9 

OK: Go to next step 

1. Disconnect the E14 switch connector.
   Fig 2: Identifying E14 switch, E1 And E2 ECU Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the E1 and E2 ECU connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E14-20 (H) - E2-17 (HEAD)	Always	Below 1 Ω
   E14-18 (T) - E1-23 (TAIL)
   E14-12 (EL) - Body ground
   E14-20 (H) - Body ground	Always	10 kΩ or higher
   E14-18 (T) - Body ground

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE MAIN BODY ECU 

1. Remove the HEAD LO relay from the engine room relay block.
   Fig 3: Identifying Headlight Relay (HEAD LO)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Battery voltage not applied to terminals 1 and 2	10 kΩ or higher
   	Battery voltage applied to terminals 1 and 2	Below 1 Ω

NG → REPLACE HEAD LO RELAY 

OK: Go to next step 

1. Remove the HEAD LO relay from the engine room relay block.
   Fig 4: Checking Harness And Connector (Headlight Relay (Head LO) - Battery)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   HEAD LO relay terminal 1 - Body ground	Always	11 to 14 V
   HEAD LO relay terminal 5 - Body ground

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

Fig 5: Identifying A40 And A46 Light Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the HEAD LO relay from the engine room relay block.
2. Disconnect the A40 and A46 light connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   for LH 

   for RH 

   Tester Connection	Condition	Specified Condition
   HEAD LO relay terminal 3 - A40-2 (LO)	Always	Below 1 Ω
   A40-6 (E) - Body ground
   A40-2 (LO) - Body ground	Always	10 kΩ or higher

   Tester Connection	Condition	Specified Condition
   HEAD LO relay terminal 3 - A46-2 (LO)	Always	Below 1 Ω
   A46-6 (E) - Body ground
   A46-2 (LO) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 2B ECU connector.
   Fig 6: Identifying 2B ECU Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using a service wire, connect terminal 2B-18 (HRLY) on the wire harness side and the body ground.
3. Check that the headlight low beam illuminates.

   OK

   Headlight low beam illuminates.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (HEAD LO RELAY - MAIN BODY ECU) 

OK → REPLACE MAIN BODY ECU