Mazda 6. Manual - part 352

ON-BOARD DIAGNOSTIC [HEADLIGHT AUTO LEVELING SYSTEM] 

T–157

T

DTC B2619

A6E816467000W09

Diagnostic procedure

DTC B2619

Rear auto leveling sensor signal system.

DETECTION 

CONDITION

Warning
• incorrect servicing of the auto leveling control unit could result in electrical shock because 

the unit is integrated with the discharge headlight control unit. Before servicing the auto 
leveling control unit, always refer to “Discharge headlight service warnings.” (See 

T–25 

DISCHARGE HEADLIGHT SERVICE WARNINGS

)

Output signal is not sent from the rear auto leveling sensor.

POSSIBLE 

CAUSE

• Rear auto leveling sensor malfunction

• Open or short circuit in wiring harness between rear auto leveling sensor and headlight (LH)

• Headlight (LH) malfunction

STEP

INSPECTION

ACTION

1

INSPECT REAR LEVELING SENSOR 

CONNECTION

• Check installation condition of rear auto 

leveling sensor and fit of connector.

• Are installation condition and fit okay?

Yes

Go to next step.

No

After correcting fit, clear DTC and check DTC again.

• If DTC is displayed again, go to next step.

2

INSPECT WIRING HARNESS BETWEEN 

REAR AUTO LEVELING SENSOR 
CONNECTOR AND HEADLIGHT (LH) 
CONNECTOR

• Disconnect rear auto leveling sensor 

connector (6-pin) and headlight (LH) 
connector (4-pin).

• Is there continuity between the following 

connectors?
— Rear auto leveling sensor connector 

(terminal B) and headlight (LH) connector 
(terminal 2D)

Yes

Go to next step.

No

Repair or replace wiring harness between rear auto leveling 
sensor and headlight (LH).

T–158

ON-BOARD DIAGNOSTIC [HEADLIGHT AUTO LEVELING SYSTEM] 

End Of Sie

DTC B2626, B2477

A6E816467000W10

Diagnostic procedure

End Of Sie

3

INSPECT WIRING HARNESS BETWEEN 

REAR AUTO LEVELING SENSOR 
CONNECTOR AND HEADLIGHT (LH) 
CONNECTOR

• Disconnect rear auto leveling sensor 

connector (6-pin) and headlight (LH) 
connector (4-pin).

• Is there no continuity between the following 

connectors?
— Rear auto leveling sensor connector 

(terminal B) and headlight (LH) connector 
(terminal 2B)

— Rear auto leveling sensor connector 

(terminal B) and headlight (LH) connector 
(terminal 2A)

Yes

Go to next step.

No

Repair or replace wiring harness between rear auto leveling 
sensor and headlight (LH).

4

INSPECT HEADLIGHT (LH)

• Disconnect auto leveling control unit (main) 

connector (20-pin) and headlight (LH) 
connector (4-pin).

• Is there continuity between the following 

connectors?
— Auto leveling control unit (main) connector 

(terminal F) and headlight (LH) connector 
(terminal 2D)

Yes

Go to next step.

No

Possible cause is an open circuit in headlight (LH). Replace 
headlight (LH). (See 

T–26 FRONT COMBINATION LIGHT 

REMOVAL/INSTALLATION

)

5

INSPECT HEADLIGHT (LH)

• Disconnect auto leveling control unit (main) 

connector (20-pin) and headlight (LH) 
connector (4-pin).

• Is there continuity between the following 

connectors?
— Auto leveling control unit (main) connector 

(terminal G) and headlight (LH) connector 
(terminal 2D)

— Auto leveling control unit (main) connector 

(terminal K) and headlight (LH) connector 
(terminal 2D)

— Auto leveling control unit (main) connector 

(terminal E) and headlight (LH) connector 
(terminal 2D)

Yes

Replace rear auto leveling sensor.
(See 

T–32 REAR AUTO LEVELING SENSOR REMOVAL/

INSTALLATION

)

No

Possible cause is an open circuit in headlight (LH). Replace 
headlight (LH). (See 

T–26 FRONT COMBINATION LIGHT 

REMOVAL/INSTALLATION

)

STEP

INSPECTION

ACTION

DTC B2626, 

B2477

Headlight zeroset system for auto leveling control unit.

DETECTION 

CONDITION

Warning
• incorrect servicing of the auto leveling control unit could result in electrical shock because 

the unit is integrated with the discharge headlight control unit. Before servicing the auto 
leveling control unit, always refer to “Discharge headlight service warnings.” (See 

T–25 

DISCHARGE HEADLIGHT SERVICE WARNINGS

)

Headlight zeroset for auto leveling control unit is not set.

POSSIBLE 

CAUSE

• Headlight zeroset for auto leveling control unit is not set or the setting is invalid

ACTION

Check connections of each sensor and the unit. Then connect WDS or equivalent and perform headlight zeroset.
(See 

T–31 HEADLIGHT ZEROSET

)

ON-BOARD DIAGNOSTIC [HEADLIGHT AUTO LEVELING SYSTEM] 

T–159

T

DTC B2735

A6E816467000W11

Diagnostic procedure

End Of Sie

DTC B2735

Headlight leveling actuator signal system.

DETECTION 

CONDITION

Warning
• incorrect servicing of the auto leveling control unit could result in electrical shock because 

the unit is integrated with the discharge headlight control unit. Before servicing the auto 
leveling control unit, always refer to “Discharge headlight service warnings.” (See 

T–25 

DISCHARGE HEADLIGHT SERVICE WARNINGS

)

Output signal to headlight leveling actuator is abnormal.

POSSIBLE 

CAUSE

• Headlight leveling actuator malfunction

• Auto leveling control unit malfunction

• Headlight malfunction

STEP

INSPECTION

ACTION

1

INSPECT CONNECTOR CONNECTION

• Check fit of auto leveling control unit.

• Is condition of the fit okay?

Yes

Possible cause is headlight wiring harness malfunction or 
malfunctioning headlight leveling acutuator.
Replace headlight and go to next step. (See 

T–26 FRONT 

COMBINATION LIGHT REMOVAL/INSTALLATION

)

No

After correcting fit, clear DTC and check DTC again.

• If DTC is displayed again, go to next step.

2

• Does headlight leveling actuator work 

properly?

Yes

Troubleshooting completed.

No

Replace auto leveling control unit.
(See 

T–30 DISCHARGE HEADLIGHT CONTROL UNIT 

REMOVAL/INSTALLATION

)

T–160

ON-BOARD DIAGNOSTIC [IMMOBILIZER SYSTEM] 

FOREWORD

A6E817067000W01

Reading DTCs procedure

• If there is a failure to display a DTC using the security light or SST (WDS or equivalent), check the symptom 

and inspect malfunctioning parts.

Caution

• When the engine does not start or stalls and the following DTCs are not indicated, go to engine 

symptom troubleshooting.

Note

• When the immobilizer system is defective, the engine cannot be started. 

• If engine condition is normal but light stays on, inspect for short circuit between security light. Repair or 

replace the wiring harness if necessary.

• The vehicle may fail to start or a DTC may be stored in the PCM if the following occurs:

— If a large, metal object is close to a valid key
— If an electrical device is close to a valid key
— If two or more valid keys are on the same key ring

• If any malfunction cannot be identified, verify that no metal object or electrical device is on the key ring.

• The security light displays a DTC 10 times.

1. Turn the ignition switch to ON position.

• If there is any malfunction, the security light flashes rapidly for approx. 1 minute and start displaying a 

DTC.

• If there is no malfunction, the security light illuminates for approx. 3 seconds and goes off.

2. Verify the security light condition and read the DTC by security light flashing pattern
3. Verify the DTC with WDS or equivalent. 
4. If the DTC is indicated, go to troubleshooting referring to the DTC table.

PID/Data Monitor and Record Procedure

1. Connect SST (WDS or equivalent) to the vehicle 

DLC-2 16-pin connector.

2. Access and monitor PIDs using SST (WDS or 

equivalent).

ON-BOARD DIAGNOSTIC [IMMOBILIZER SYSTEM]

Symptom

Possibly malfunctioning part

Security light is stuck on or does not illuminate.

• Instrument cluster (security light)

• PCM

• Related harness

Engine does not start.
(When ignition switch is turned to ON, security light illuminates 
for approx. 3 seconds and goes off.)

• PCM

• Stater relay

• Key (transponder)

• Key ID number

• Related harness

DLC-2

A6E3970W002