Suzuki Grand Vitara JB416 / JB420. Manual - part 410

10B-6 Body Electrical Control System: 

Diagnostic Information and Procedures

BCM Self-Diagnosis Function

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• BCM monitors conditions of the system components and its circuit with ignition switch turned to ON position. When 

an abnormality in the system occurs, the area where that abnormality lies is stored in the memory of EEPROM in 
BCM.

• DTC can be checked in either one of following ways.

– DTC can be checked by SUZUKI scan tool (2) connected to DLC (1).
– DTC can be read from flashing pattern of theft deterrent light (3). In addition, when theft deterrent light is flashing 

for DTC outputting DTC is displayed on combinations meter (4) at the same time.

BCM input / output table

7. Door switch

17. Hazard warning switch

27. Front fog light switch

8. Interior light

18. Rear wiper switch

28. Turn signal and hazard warning relay

9. Luggage room light

19. Lighting switch

29.  Key reminder switch (included in ignition switch)

10. Rear end door lock actuator 

(incorporated in door switch)

20. Manual door lock switch

3

1

2

4

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Control

Input

Output

Power door lock system

• Key cylinder switch
• Manual door lock switch

• Driver side door lock actuator
• Other than driver side door lock 

actuator

Keyless entry system

• Key reminder switch
• Keyless entry receiver
• Driver side door switch

• Driver side door lock actuator
• Other than driver side door lock 

actuator

• Turn signal and hazard warning relay
• Interior light

Keyless start system
(Door lock function)

• Keyless start control module

• Driver side door lock actuator
• Other than driver side door lock 

actuator

• Turn signal and hazard warning relay
• Interior light

Rear wiper 

• Rear wiper INT switch
• Rear wiper LO switch

• Rear wiper relay

Body Electrical Control System:  10B-7

Combination meter

• Lighting switch
• Brake fluid level switch
• Seat belt reminder lamp signal
• Generator
• Oil presser switch
• Parking brake switch
• Power/Normal mode select switch (for A/T 

model only)

• Dimmer switch (high beam)
• Illumination controller (for auto-on headlight 

model only)

• Door switch
• BCM DTC signal

• Combination meter

Interior light

• Each door switch
• Key reminder switch

• Interior light
• Luggage room light

Warning buzzer

• Key reminder switch
• Tail light switch
• Driver side door switch
• ECM (vehicle speed signal)
• TCM (reverse signal) (if equipped)
• 4WD control module (for 4WD model only)
• Keyless start control module (if equipped)

• Warning buzzer (located in BCM)

DRL system

• Lighting switch
• ECM (engine ON, OFF signal)
• Generator

• DRL indicator lamp control signal
• Headlight low relay

Auto-on headlight system

• Lighting switch
• Parking brake switch
• Auto-on headlight sensor

• Tail light relay
• Headlight low relay

Front fog light

• Lighting switch
• Front fog light switch

• Front fog light relay

Rear end door window 
defogger and door mirror 
heater

• Rear end door window defogger switch 

(included in HVAC control module)

• Generator
• ECM (engine ON, OFF signal)

• Rear end door defogger window 

relay

• Mirror heater relay (if equipped)

Illumination control (if 
equipped)

• Lighting switch
• Illumination controller

• Illumination control of combination 

meter and information display 
(illumination cancel signal)

Door lock canceller

• SDM (air bag deployment signal)

• Driver side door lock actuator
• Other than driver side door lock 

actuator

Theft deterrent light

• Key reminder switch

• Theft deterrent light (located in HVAC 

control module)

Control

Input

Output

10B-8 Body Electrical Control System: 

Body Electrical Control System Check

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Step

Action

Yes

No

1

)

 Customer complaint analysis

1) Perform customer complaint analysis.

Was customer complaint analysis performed?

Go to Step 2.

Perform customer 
complaint analysis.

2

)

 Problem symptom confirmation

1) Perform problem symptom confirmation.

Does trouble recur?

Go to Step 3.

Go to Step 7.

3

)

 DTC check

1) Check DTC.

Is it malfunction code?

Go to Step 4.

Go to Step 5.

4

)

 Troubleshooting for DTC

1) Check and repair according to DTC diag. flow.

Are check and repair completed?

Go to Step 7.

Check and repair 
malfunction part(s).

5

)

 Body electrical control system symptom diagnosis

1) Perform check and repair referring to “Symptom 

Diagnosis” of system having a trouble.

Is there faulty condition?

Repair or replace 
malfunction part(s).

Go to Step 6.

6

)

 Check for intermittent problem

1) Check for intermittent problem.

Is there faulty condition?

Repair or replace 
malfunction part(s).

Go to Step 7.

7

)

 Final confirmation test

1) Clear DTC referring to “DTC Clearance”.
2) Check DTC referring to “DTC Check”.

Is there any DTC?

Go to Step 4.

End.

Body Electrical Control System:  10B-9

Customer Complaint Analysis
Record details of the problem (failure, complaint) and how it occurred as described by the customer.
For this purpose, use of such a questionnaire form as shown in the figure will facilitate collecting information to the 
point required for proper analysis and diagnosis.

Customer questionnaire (example)

Problem Symptom Confirmation
Check if what the customer claimed in “Customer Questionnaire” is accurately found in the vehicle. If that symptom is 
found, check whether the symptom is identified as a failure. (This step should be shared with the customer if possible.)

DTC check
Check DTC stored in BCM memory referring to “DTC Check”, record it and then clear it referring to “DTC Clearance”. 
DTC indicates malfunction that occurred in the system but does not indicate whether it exists now or it occurred in the 
past and the normal condition has been restored now. To check which case applies, clear DTC once and check 
whether or not any fault exists.

Troubleshooting for DTC
Based on the DTC indicated in Step 3 and referring to applicable DTC flow, locate the cause of the trouble, namely in 
a sensor, wire harness, connector, BCM or other part and repair or replace faulty parts.

Body Electrical Control System Symptom Diagnosis
Check the parts or system suspected as a possible cause referring to symptom diagnosis of each system.

Check for Intermittent Problem
Check parts where an intermittent trouble is easy to occur (e.g., wire harness, connector, etc.), referring to 
“Intermittent and Poor Connection Inspection in Section 00”.

Final Confirmation Test
Confirm that the problem symptom has gone and the body electrical control system is free from any abnormal 
conditions. If what has been repaired is related to the malfunction DTC, check DTC again and confirm that no DTC is 
indicated.

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