RM38N0EC _59 Vehicle Exterior _111834 LIGHTING (EXT) _0499887 LIGHTING SYSTEM C

LIGHTING (EXT)  LIGHTING SYSTEM  B243949  Headlight LH Circuit Internal Electronic Failure  B243A49  Headlight RH Circuit Internal Electronic Failure  


DESCRIPTION

The headlight assembly internally boost the power supply voltage to ensure a constant supplied current for the low beam LED of their respective headlight.

These DTCs are also output when the main body ECU (multiplex network body ECU) detects malfunctions while monitoring the applied voltage.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from
B243949 Headlight LH Circuit Internal Electronic Failure
Detection condition:

Ignition switch is to ON, low beam headlights illuminated


Malfunction status:
·

Headlight assembly LH malfunction

·

Headlight assembly LH power source and signal malfunction


Malfunction duration:

10 seconds or more


·

Headlight assembly LH

·

H-LP LH relay

·

Power distribution box assembly

·

Main body ECU (multiplex network body ECU)

·

Harness or connector


Main Body
B243A49 Headlight RH Circuit Internal Electronic Failure
Detection condition:

Ignition switch is to ON, low beam headlights illuminated


Malfunction status:
·

Headlight assembly RH malfunction

·

Headlight assembly RH power source and signal malfunction


Malfunction duration:

10 seconds or more


·

Headlight assembly RH

·

H-LP RH relay

·

Power distribution box assembly

·

Main body ECU (multiplex network body ECU)

·

Harness or connector


Main Body

WIRING DIAGRAM

E480215E02
1.052,0.5 2.885,0.698 1.833,0.198 10 false from Auxiliary Battery 0.688,1.177 2.521,1.375 1.833,0.198 10 false H-LP LH 2.094,1.594 2.74,1.844 0.646,0.25 10 false H-LP LH 2.073,3.063 2.719,3.313 0.646,0.25 10 false H-LP RH 0.708,2.635 1.354,2.885 0.646,0.25 10 false H-LP RH 4.281,2.854 4.927,3.104 0.646,0.25 10 false 4D 4.021,0.885 4.667,1.135 0.646,0.25 10 false 6 2.635,0.885 2.833,1.094 0.198,0.208 10 false 1 1.99,0.906 2.188,1.115 0.198,0.208 10 false 2 1.969,1.208 2.167,1.417 0.198,0.208 10 false 5 2.646,1.177 2.844,1.385 0.198,0.208 10 false 3 5.719,0.813 6.365,1.063 0.646,0.25 10 false 8 5.656,1 6,1.177 0.344,0.177 10 false MB 6.083,0.906 6.729,1.156 0.646,0.25 10 false HRLY 2.615,3.677 3.26,3.927 0.646,0.25 10 false LO 1.885,4.094 2.531,4.344 0.646,0.25 10 false E 2.719,3.99 3.365,4.24 0.646,0.25 10 false S 1.844,4.458 3.573,4.656 1.729,0.198 10 false A94 5.688,3.792 6.333,4.042 0.646,0.25 10 false 13 6.594,3.51 6.854,3.76 0.26,0.25 10 false IG 6.573,5.302 6.833,5.552 0.26,0.25 10 false IG 6.042,3.885 6.688,4.135 0.646,0.25 10 false RLEW 6.042,5.698 6.688,5.948 0.646,0.25 10 false LLEW 5.688,5.594 6.031,5.792 0.344,0.198 10 false 12 5.635,5.802 6,6.01 0.365,0.208 10 false E36 2.719,5.771 3.365,6.021 0.646,0.25 10 false S 2.656,5.49 3.302,5.74 0.646,0.25 10 false LO 1.885,5.885 2.531,6.135 0.646,0.25 10 false E 1.844,4.604 3.792,4.927 1.948,0.323 10 false Headlight Assembly RH 1.76,6.438 3.698,6.677 1.938,0.24 10 false Headlight Assembly LH 1.958,2.677 2.156,2.885 0.198,0.208 10 false 5 1.948,2.344 2.146,2.552 0.198,0.208 10 false 2 2.656,2.615 2.854,2.823 0.198,0.208 10 false 3 2.646,2.354 2.844,2.563 0.198,0.208 10 false 1 6.042,2.365 6.688,2.615 0.646,0.25 10 false HRY2 5.635,3.99 6.115,4.229 0.479,0.24 10 false E36 5.5,6.281 7.146,6.771 1.646,0.49 10 false Main Body ECU (Multiplex Network Body ECU) 4.281,3.021 5.76,3.469 1.479,0.448 10 false Power Distribution Box Assembly 2.938,3.583 3.135,3.802 0.198,0.219 10 false 4 2.917,3.885 3.74,4.094 0.823,0.208 10 false 2 1.708,4 1.885,4.198 0.177,0.198 10 false 5 2.938,5.375 3.135,5.583 0.198,0.208 10 false 4 1.698,5.76 1.833,5.958 0.135,0.198 10 false 5 1.031,1.938 2.865,2.135 1.833,0.198 10 false from Auxiliary Battery 3.969,2.344 4.615,2.594 0.646,0.25 10 false 10 5.708,2.25 5.927,2.438 0.219,0.188 10 false 9 1.781,6.271 3.51,6.469 1.729,0.198 10 false A95 2.927,5.708 3.75,5.917 0.823,0.208 10 false 2 5.667,2.448 6.01,2.625 0.344,0.177 10 false MB

CAUTION / NOTICE / HINT

NOTICE:
·

Inspect the fuses for circuits related to this system before performing the following procedure.

·

Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.



PROCEDURE

1.CLEAR DTC
a.

Clear the DTCs.

Body Electrical > Main Body > Clear DTCs
50002 449

Result:
Proceed to
NEXT



NEXT

2.CHECK FOR DTC
2.CHECK FOR DTC
a.

Turn the ignition switch to ON.


b.

Operate the light control switch to turn on the low beam headlights and wait 10 seconds or more.


c.

Check for DTCs.

Body Electrical > Main Body > Trouble Codes
50001 449
OK:

DTC B243949 and B243A49 are not output.



Result:
Result Proceed to
OK A
NG (DTC B243949 is output) B
NG (DTC B243A49 is output) C



A

USE SIMULATION METHOD TO CHECK

Click hereGeneral>INTRODUCTION>HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS>HOW TO PROCEED WITH TROUBLESHOOTING


B

3.CHECK HEADLIGHT ASSEMBLY LH (LO TERMINAL VOLTAGE)

C

12.CHECK HEADLIGHT ASSEMBLY RH (LO TERMINAL VOLTAGE)
3.CHECK HEADLIGHT ASSEMBLY LH (LO TERMINAL VOLTAGE)
a.
E480218C01
1.427,0.25 1.969,0.49 0.542,0.24 1.99,1.188 2.646,0.771 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.292 2.031,0.49 0.458,0.198 10 false A95 2.646,0.583 3.104,0.781 0.458,0.198 10 false LO
*a Front view of wire harness connector
(to Headlight Assembly LH)


Disconnect the headlight assembly LH connector.


b.

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

Standard Voltage:
Tester Connection Switch Condition Specified Condition

Click Location & Routing(A95)Location & Routing

Click Connector(A95)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly LH

A95-4 (LO) - Body ground Light control switch in HEAD position 11 to 14 V



Result:
Proceed to
OK
NG



OK

4.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY LH - BODY GROUND)

NG

7.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT ASSEMBLY LH)
4.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY LH - BODY GROUND)
a.
E480218C02
1.427,0.25 1.969,0.49 0.542,0.24 0.75,1.844 1.406,1.427 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.292 2.031,0.49 0.458,0.198 10 false A95 0.635,1.833 1.094,2.031 0.458,0.198 10 false E
*a Front view of wire harness connector
(to Headlight Assembly LH)


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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A95)Location & Routing

Click Connector(A95)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly LH

A95-5 (E) - Body ground Always Below 1 Ω



Result:
Proceed to
OK
NG



OK

5.CHECK HEADLIGHT ASSEMBLY LH (S TERMINAL VOLTAGE)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.CHECK HEADLIGHT ASSEMBLY LH (S TERMINAL VOLTAGE)
a.
E480218C03
1.427,0.25 1.969,0.49 0.542,0.24 0.76,1.646 1.563,1.24 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.292 2.031,0.49 0.458,0.198 10 false A95 0.646,1.583 1.104,1.781 0.458,0.198 10 false S
*a Front view of wire harness connector
(to Headlight Assembly LH)


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

Standard Voltage:
Tester Connection Switch Condition Specified Condition

Click Location & Routing(A95)Location & Routing

Click Connector(A95)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly LH

A95-2 (S) - Body ground Ignition switch ON 11 to 14 V



Result:
Proceed to
OK
NG



OK

REPLACE HEADLIGHT ASSEMBLY LH

Click hereVehicle Exterior>LIGHTING (EXT)>HEADLIGHT ASSEMBLY>REMOVAL


NG

6.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY LH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
6.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY LH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
a.

Disconnect the E36 main body ECU (multiplex network body ECU) connector.


b.

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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A95,E36)Location & Routing

Click Connector(A95)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly LH

Click Connector(E36)Instrument Panel>Instrument Panel Wire / Telephone Computer Wire>Multiplex Network Body ECU

A95-2 (S) - E36-12 (LLEW) Always Below 1 Ω
A95-2 (S) or E36-12 (LLEW) - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT ASSEMBLY LH)
a.

Remove the H-LP LH relay.


b.

Disconnect the A95 headlight assembly LH connector.


c.

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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A95)Location & Routing

Click Connector(A95)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly LH

3 (H-LP LH relay) - A95-4 (LO) Always Below 1 Ω
3 (H-LP LH relay) or A95-4 (LO) - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

8.INSPECT H-LP LH RELAY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.INSPECT H-LP LH RELAY

Click hereVehicle Exterior>LIGHTING (EXT)>RELAY>ON-VEHICLE INSPECTION

Result:
Proceed to
OK
NG



OK

9.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - AUXILIARY BATTERY)

NG

REPLACE H-LP LH RELAY

9.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - AUXILIARY BATTERY)
a.
B340809C08
0.115,0.083 0.427,0.281 0.313,0.198 10 false *a
*a Front view of wire harness connector
(to H-LP LH Relay)


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

Standard Voltage:
Tester Connection Switch Condition Specified Condition
2 (H-LP LH relay) - Body ground Ignition switch off 11 to 14 V
5 (H-LP LH relay) - Body ground Ignition switch off 11 to 14 V



Result:
Proceed to
OK
NG



OK

10.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - POWER DISTRIBUTION BOX ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

10.CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - POWER DISTRIBUTION BOX ASSEMBLY)
a.

Disconnect the 4D power distribution box assembly connector.


b.

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

Standard Resistance:
Tester Connection Condition Specified Condition
1 (H-LP LH relay) - 4D-6 Always Below 1 Ω
1 (H-LP LH relay) or 4D-6 - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

11.CHECK POWER DISTRIBUTION BOX ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.CHECK POWER DISTRIBUTION BOX ASSEMBLY
a.

Remove the power distribution box assembly.

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL

E443881C15
1.438,0.073 1.854,0.333 0.417,0.26 5.313,0.302 5.729,0.563 0.417,0.26 4.396,1.302 4.552,1.302 4.552,1.302 4.792,0.927 true 0.104,0.083 0.417,0.281 0.313,0.198 10 false *a 1.573,0.125 1.885,0.323 0.313,0.198 10 false 4D 5.406,0.354 5.719,0.552 0.313,0.198 10 false MB 4,1.198 4.615,1.396 0.615,0.198 10 false HRLY
*a Component without harness connected
(Power Distribution Box Assembly) 		- -



b.

Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


c.

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

Standard Resistance:
Tester Connection Condition Specified Condition
4D-6 - MB-8 (HRLY) Always Below 1 Ω



Result:
Proceed to
OK
NG



OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


NG

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


12.CHECK HEADLIGHT ASSEMBLY RH (LO TERMINAL VOLTAGE)
a.
E480218C04
1.438,0.271 1.979,0.51 0.542,0.24 1.99,1.188 2.646,0.771 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.313 2.031,0.51 0.458,0.198 10 false A94 2.646,0.583 3.104,0.781 0.458,0.198 10 false LO
*a Front view of wire harness connector
(to Headlight Assembly RH)


Disconnect the headlight assembly RH connector.


b.

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

Standard Voltage:
Tester Connection Switch Condition Specified Condition

Click Location & Routing(A94)Location & Routing

Click Connector(A94)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly RH

A94-4 (LO) - Body ground Light control switch in HEAD position 11 to 14 V



Result:
Proceed to
OK
NG



OK

13.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY RH - BODY GROUND)

NG

16.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - HEADLIGHT ASSEMBLY RH)
13.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY RH - BODY GROUND)
a.
E480218C05
1.427,0.25 1.969,0.49 0.542,0.24 0.75,1.844 1.406,1.427 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.292 2.031,0.49 0.458,0.198 10 false A94 0.635,1.833 1.094,2.031 0.458,0.198 10 false E
*a Front view of wire harness connector
(to Headlight Assembly RH)


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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A94)Location & Routing

Click Connector(A94)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly RH

A94-5 (E) - Body ground Always Below 1 Ω



Result:
Proceed to
OK
NG



OK

14.CHECK HEADLIGHT ASSEMBLY RH (S TERMINAL VOLTAGE)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

14.CHECK HEADLIGHT ASSEMBLY RH (S TERMINAL VOLTAGE)
a.
E480218C06
1.427,0.25 1.969,0.49 0.542,0.24 0.76,1.646 1.563,1.24 false 0.677,0.25 1.135,0.448 0.458,0.198 10 false *a 1.573,0.292 2.031,0.49 0.458,0.198 10 false A94 0.646,1.583 1.104,1.781 0.458,0.198 10 false S
*a Front view of wire harness connector
(to Headlight Assembly RH)


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

Standard Voltage:
Tester Connection Switch Condition Specified Condition

Click Location & Routing(A94)Location & Routing

Click Connector(A94)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly RH

A94-2 (S) - Body ground Ignition switch ON 11 to 14 V



Result:
Proceed to
OK
NG



OK

REPLACE HEADLIGHT ASSEMBLY RH

Click hereVehicle Exterior>LIGHTING (EXT)>HEADLIGHT ASSEMBLY>REMOVAL


NG

15.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY RH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
15.CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY RH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
a.

Disconnect the E36 main body ECU (multiplex network body ECU) connector.


b.

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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A94,E36)Location & Routing

Click Connector(A94)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly RH

Click Connector(E36)Instrument Panel>Instrument Panel Wire / Telephone Computer Wire>Multiplex Network Body ECU

A94-2 (S) - E36-13 (RLEW) Always Below 1 Ω
A94-2 (S) or E36-13 (RLEW) - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

16.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - HEADLIGHT ASSEMBLY RH)
a.

Remove the H-LP RH relay.


b.

Disconnect the A94 headlight assembly RH connector.


c.

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

Standard Resistance:
Tester Connection Condition Specified Condition

Click Location & Routing(A94)Location & Routing

Click Connector(A94)Engine Compartment>Engine Room Main Wire / Transmission Wire>Headlight Assembly RH

3 (H-LP RH relay) - A94-4 (LO) Always Below 1 Ω
3 (H-LP RH relay) or A94-4 (LO) - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

17.INSPECT H-LP RH RELAY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

17.INSPECT H-LP RH RELAY

Click hereVehicle Exterior>LIGHTING (EXT)>RELAY>ON-VEHICLE INSPECTION

Result:
Proceed to
OK
NG



OK

18.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - AUXILIARY BATTERY)

NG

REPLACE H-LP RH RELAY

18.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - AUXILIARY BATTERY)
a.
B340809C08
0.115,0.083 0.427,0.281 0.313,0.198 10 false *a
*a Front view of wire harness connector
(to H-LP RH Relay)


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

Standard Voltage:
Tester Connection Switch Condition Specified Condition
2 (H-LP RH relay) - Body ground Ignition switch off 11 to 14 V
5 (H-LP RH relay) - Body ground Ignition switch off 11 to 14 V



Result:
Proceed to
OK
NG



OK

19.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - POWER DISTRIBUTION BOX ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

19.CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - POWER DISTRIBUTION BOX ASSEMBLY)
a.

Disconnect the 4D power distribution box assembly connector.


b.

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

Standard Resistance:
Tester Connection Condition Specified Condition
1 (H-LP RH relay) - 4D-10 Always Below 1 Ω
1 (H-LP RH relay) or 4D-10 - Body ground Always 10 kΩ or higher



Result:
Proceed to
OK
NG



OK

20.CHECK POWER DISTRIBUTION BOX ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

20.CHECK POWER DISTRIBUTION BOX ASSEMBLY
a.

Remove the power distribution box assembly.

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL

E443881C16
1.438,0.073 1.854,0.333 0.417,0.26 5.313,0.302 5.729,0.563 0.417,0.26 4.49,1.302 4.646,1.302 4.646,1.302 4.885,0.927 true 0.104,0.083 0.417,0.281 0.313,0.198 10 false *a 1.573,0.125 1.885,0.323 0.313,0.198 10 false 4D 5.406,0.354 5.719,0.552 0.313,0.198 10 false MB 4.094,1.219 4.708,1.417 0.615,0.198 10 false HRY2
*a Component without harness connected
(Power Distribution Box Assembly) 		- -



b.

Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


c.

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

Standard Resistance:
Tester Connection Condition Specified Condition
4D-10 - MB-9 (HRY2) Always Below 1 Ω



Result:
Proceed to
OK
NG



OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL


NG

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

Click herePower Source / Network>POWER DISTRIBUTION>MAIN BODY ECU>REMOVAL