section 10 SUZUKI SWIFT 2008 2.G Service Workshop Manual

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Control Systems
Body Electrical Control System
Precautions
Precautions in Diagnosing TroubleS7RS0BA200001
• Diagnostic information stored in BCM memory can be cleared as well as checked by using SUZUKI scan tool.
Before using scan tool, read its Operator ’s (Instruction) Manual carefully to have good understanding as to what
functions are available and how to use it.
• Be sure to read “Precautions for Electrical Circuit Serv ice in Section 00” before inspection and observe what is
written there.
• Communication of ECM, TCM (if equipped), ABS/ESP ® control module, steering angle sensor (ESP ® model),
keyless start control module (if equipped), combinatio n meter and BCM is established by CAN (Controller Area
Network). For detail of CAN communication for BCM, refer to “CAN Communication System Description”.
Therefore, handle CAN communication line with care referr ing to “Precaution for CAN Communication System in
Section 00”.
General Description
BCM General DescriptionS7RS0BA201001
The Body electrical Control Module (BCM) is incorporated in junction block assembly. Do not attempt removal of BCM
from junction block assembly as it may cause contact failure.
The BCM incorporates relays and controllers which are used for the following systems and controls them.
• Power door lock
• Keyless entry (if equipped)
• Door lock function of keyle ss start system (if equipped)
• Rear wiper
• Combination meter
• Interior light
• Warning buzzer
• Rear end door window defogger and door mirror heater (if equipped)
• Rear end door opener
• Theft deterrent light
Also, the BCM has a function to cause the interior light and open door warning lamp in the combination meter to turn
off when any door is left open for longer than 15 minutes to reduce wasteful battery consumption.
In addition, it is possible to check operation of actuator whic h is controlled by BCM by using the output test function of
SUZUKI scan tool to operate actuator simulatively.

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CAN Communication System DescriptionS7RS0BA201002
Refer to “CAN Communication System Description in Section 1A” for CAN communication system description. BCM
communication control data with ea ch control module as follows.
BCM Transmission Data
BCM Reception Data
A/C switch ON signal
Electric load signal
"3" position switch signal
Illumination ON signal
Brake fluid level switch signal
Parking brake switch signal
Seat belt buckle switch signal
Charging system signal
Engine oil pressure switch signal
Diagnostic trouble code (DTC)
Door switch status
Door lock status ECM
TCM
(A/T model) Combination
Meter Keyless Start
Control Module
(if equipped)
Transmit DATA
BCM
ESP
Control Module
(if equipped)
I7RS0BA20002-01
Engine speed signal
Vehicle speed signal Engine coolant temperature signal
A/C refrigerant pressure signal
Fuel consumption signal A/C compressor clutch signal
Transmission range sensor signal
Fuel level signal
Ignition knob switch signal
Door lock/unlock request signal
Buzzer request signal
Answer back request signal
DATA
BCM
Receive
Combination
Meter
TCM
(A/T model) Keyless Start
Control Module (if equipped)
ECM
I7RS0AA20001-01

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Input / Output Table
Schematic and Routing Diagram
Body Electrical Control System Wiring Circuit DiagramS7RS0BA202001
NOTE
This wiring diagram shows circuits related to only BCM, not the entire circuits of BCM and junction
block. Refer to “Power Supply Diagram in Section 9A” for wiring circuits other than the figure below.

Input Output
Keyless entry transmitter
Door switch status
Door lock status BCMHorn relay
Theft deterrent light
(in information display)
Warning buzzer
(located in BCM)
Hazard warning relay
Door request switch signal
Ignition switch
I5RS0CA20003-01

Downloaded from www.Manualslib.com manuals search engine 10B-11 Body Electrical Control System:
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 figure will facilitate collectin g information to the point
required for proper analysis and diagnosis. Customer questionnaire (example)
Problem Symptom Confirmation
Check if what the custom er claimed in “Customer
Questionnaire” is accurately f ound 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 me mory 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 Intermi ttent Problem
Check parts where an intermit tent trouble is easy to
occur (e.g., wire harness, connector, etc.), referring to
“Intermittent and Poor Connec tion 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.
Customers name:
Model:
VIN:

Date of issue:
Date Reg:
Date of problem:
Mileage:

Problem Symptoms
Power door lock system does not operate
Keyless entry system does not operate
Rear end door window defogger does not operate
Rear wiper does not operate
Rear end door opener does not operate
Other
Frequency of Occurrence
Continuous / Intermittent ( times a day, a month)
/ Other

Environmental Condition
Weather:
Fine / Cloudy / Rain / Snow / Other

Temperature: (F )
Diagnostic Trouble Code Normal code / Malfunction code ( )

Warning buzzer does not sound
Interior light does not light
Theft deterrent light does not flush
I5RS0DA20006-01

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DTC B1133 (DTC No. 1133): Battery Voltage Too HighS7RS0BA204008
Wiring Diagram
Refer to “BCM Power Circuit and Ground Circuit Check”.
DTC Detecting Conditi on and Possible Cause
Flow Test Description
Step 1: Check charging system
DTC Troubleshooting 3
Power supply circuit check
1) Check for proper connection to junction block assembly
connector at terminals “G32-2” and “G32-5”.
2) If OK, turn ignition switch ON.
3) Measure voltage between following terminals. • Between “G32-2” terminal of junction block assembly connector and vehicle body ground
• Between “G32-5” terminal of junction block assembly connector and vehicle body ground
Is each voltage 10 – 14 V? Go to Step 4. Repair power supply
circuit.
4 Ground circuit check
1) Turn ignition switch to OFF position.
2) Check for proper connection to junction block assembly
connector at terminals “G33-3”, “G34-9” and “L05-4”.
3) If OK, then measure resistance between following terminals.
• Between “G33-3” terminal of junction block assembly connector and vehicle body ground
• Between “G34-9” terminal of junction block assembly connector and vehicle body ground
• Between “L05-4” terminal of junction block assembly connector and vehicle body ground
Is each resistance 2
Ω or less? BCM power supply
circuit and ground circuit
are in good condition.
Repair ground circuit.
Step Action Yes No
DTC detecting condition
Possible cause
Power voltage supplied from battery to BCM is
higher than 16V. • Charging system malfunction
• BCM malfunction
Step
Action YesNo
1 Charging system operation check
1) Check generator for operation referring to “Generator
Test (Overcharged Battery Check) in Section 1J”.
Is it in good condition? Substitute a known
good BCM (included in
junction block
assembly) and recheck.
Repair charging system.

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DTC B1141 / DTC B1142 (No. 1141 / No. 1142): Outside Air Temperature (Ambient Temp.) Sensor
Circuit Malfunction
S7RS0BA204009
Wiring Diagram
DTC Detecting Condition and Possible Cause
Flow Test Description
Step 1: Check whether malfunction is in outside air temperature sensor.
Step 2: Check outside air temperature sensor input circuit.
Step 3: Check outside air temperature sensor ground circuit (for DTC B1141).
DTC Troubleshooting
I4RS0AA20010-01
[A]: BCM connector viewed from harness side 3. Junction block assembly
1. Outside air temperature sensor 4. Outside air temperature sensor connector
2. BCM
DTC detecting condition Possible cause
DTC B1141 (DTC No. 1141):
Input signal from outside air temperature sensor is higher
than 4.88 V. • Open in outside air temperature sensor circuit
• Outside air temperature sensor malfunction
• BCM malfunction
DTC B1142 (DTC No. 1142):
Input signal from outside air temperature sensor is lower
than 0.1 V. • Short in outside air temperature sensor circuit
• Outside air temperature sensor malfunction
• BCM malfunction
Step
Action YesNo
1 Check outside air temperature sensor
1) Turn ignition switch to OFF position.
2) Disconnect connector from outside air temperature
sensor.
3) Check outside air temperature sensor for resistance referring to “Outside Air Temperature Sensor Inspection
(If Equipped) in Section 9C”.
Is it in good condition? Go to Step 2.
Replace outside air
temperature sensor.

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DTC Troubleshooting
DTC B1157 (No. 1157): Air Bag Deployment Signal InputS7RS0BA204011
Wiring Diagram
Refer to “DTC B1150 (No. 1150): Air Bag Communication Circuit Malfunction”.
DTC Detecting Conditi on and Possible Cause
Flow Test Description
Step 1: Check DTC for SDM.
DTC Troubleshooting Step Action Yes No
1 Check air bag communication circuit
1) Turn ignition switch to OFF position.
2) Disconnect connector from SDM referring to “SDM
Removal and Installation in Section 8B”.
3) Disconnect connector from junction block assembly.
4) Turn ignition switch to ON position.
5) Measure voltage between “L29-37” terminal of SDM connector and vehicle body ground.
Is voltage 0 V? Go to Step 2. Short to power supply in
air bag communication
circuit.
2 Check air bag communication circuit
1) Turn ignition switch to OFF position.
2) Connect connectors to junction block assembly.
3) Turn ignition switch to ON position.
4) Measure voltage between “L04-2” terminal of junction
block assembly connector and vehicle body ground.
Is voltage 4 – 6 V? Go to Step 3.
Short to ground in air
bag communication
circuit. If OK, substitute
a known-good BCM
(included in junction
block assembly) and
recheck.
3 Check air bag communication circuit
1) Measure voltage between “L29-37” terminal of SDM
connector and vehicle body ground.
Is voltage 4 – 6 V? Substitute a known-
good SDM and recheck.
Open or high resistance
in air bag
communication circuit.
DTC detecting condition
Possible cause
Air bag deployment signal is fed from SDM to BCM. • Air bag component parts
• BCM malfunction
StepAction YesNo
1 DTC check of SDM
1) Check DTC stored in SDM re ferring to “DTC Check in
Section 8B”.
Is DTC B1021 detected? Go to “DTC B1021:
Front Air Bag Module
Deployed in Section
8B”.
Substitute a known-
good BCM (included in
junction block
assembly) and recheck.

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DTC TroubleshootingStep Action YesNo
1 DTC check of BCM
Is DTC U0155 (No. 0155) and DTC U1073 (No. 1073)
detected together? Go to “DTC U1073 (No.
1073): Control Module
Communication Bus
Off”.Go to Step 2.
2 Control module connector check
1) Check connection of connectors of all control modules
communicating by means of CAN.
2) Recheck BCM for DTC.
Is DTC U0155 (No. 0155) detected? Go to Step 3.
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
3 Combination meter power and ground circuit check
1) Turn ignition switch to ON position.
Do warning lights in combi nation meter other than key
indicator light light up? Go to Step 4.
Check combination
meter power and
ground circuit. If circuit
is OK, substitute a
known-good
combination meter and
recheck.
4 CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from BCM, combination meter
and steering angle sensor (ESP ® model).
3) Check CAN communication circuit between BCM and combination meter for open, short and high resistance.
Is each CAN communication circuit in good condition? Go to Step 5.
Repair circuit.
5 CAN communication circuit check
1) Disconnect connectors of all control modules
communicating by means of CAN.
2) Check CAN communication circuit between control modules other than Step 4 for open, short and high
resistance.
Is each CAN communication circuit in good condition? Go to Step 6.
Repair circuit.
6 DTC check of BCM
1) Connect connectors of disconnected control modules
communicating by means of CAN.
2) Disconnect connector of any one of control module other than BCM.
3) Recheck BCM for DTC.
Is DTC U0155 (No.0155) detected? Disconnect connectors
of control modules other
than the one whose
connector is
disconnected in Step 2)
one by one and check
that DTC U0155 is
detected by BCM each
time connector is
disconnected. When
DTC U0155 is not
detected by BCM while
checking in this way, go
to description under
“NO” below. If DTC
U0155 is detected by
BCM even when
connectors of all control
modules that use CAN
communication with
BCM are disconnected,
substitute a known-
good BCM and recheck.Check power and
ground circuit of control
module disconnected in
Step 2). If circuit is OK,
substitute a known-
good control module
disconnected in Step 2)
and recheck.

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DTC U1073 (No. 1073): Control Module Communication Bus OffS7RS0BA204014
Wiring Diagram
Refer to “DTC U0155 (No. 0155): Lost Communication with Instrument Panel Cluster (IPC) Control Module”.
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure 1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC by using scan tool.
3) Start engine and run it for 1 min. or more.
4) Check DTC.
DTC Troubleshooting DTC detecting condition Trouble area
Transmission error that is inconsistent between transmission data and
transmission monitor (CAN bus monitor) data is detected more than 7
times continuously.
(1 driving detection logic) • CAN communication circuit
• Combination meter
• BCM (included in junction block
assembly)
• TCM (A/T model)
• ABS/ESP ® control module
• Keyless start control module (if equipped)
•ECM
• Steering angle sensor (if equipped)
Step Action YesNo
1 Control module connector check
1) Check connection of connectors of all control modules
communicating by means of CAN.
2) Recheck DTC.
Is DTC U1073 detected? Go to Step 2.
Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
2 CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors of all control modules
communicating by means of CAN.
3) Check CAN communication circuit between control modules for open, short and high resistance.
Is each CAN communication circuit in good condition? Go to Step 3.
Repair circuit.

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DTC TroubleshootingStep Action Yes No 1 DTC check of BCM
Is DTC U1100 (No. 1100) and DTC U1073 (No. 1073)
detected together? Go to “DTC U1073 (No.
1073): Control Module
Communication Bus
Off”.Go to Step 2.
2 DTC check of ECM
1) Check ECM for DTC.
Is DTC P1674 detected? Go to “DTC P1674:
CAN Communication
(Bus Off Error) in
Section 1A”.Go to Step 3.
3 DTC check of ABS/ESP ® control module
1) Check ABS/ESP ® control module for DTC.
Is DTC U1073 detected? Go to “DTC U1073:
Control Module
Communication Bus Off
in Section 4E” or “DTC
U1073: Control Module
Communication Bus Off
in Section 4F”.Go to Step 4.
4 Control module connector check
1) Check connection of connectors of all control modules
communicating by means of CAN.
2) Recheck BCM for DTC.
Is DTC U1100 (No. 1100) detected? Go to Step 5. Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section
00”.
5 DTC check of ABS/ESP ® control module
1) Check DTC for ABS/ESP ® control module.
Is DTC U1100 detected? Go to Step 6. Go to Step 7.
6 CAN communication circuit check
1) Disconnect connector s from ECM and ABS/ESP ®
control module.
2) Check CAN communication circuit between ECM and ABS/ESP ® control module for open, short and high
resistance.
Is each CAN communication circuit in good condition? Check ECM power and
ground circuit. If circuit
is OK, substitute a
known-good ECM and
recheck.
Repair circuit.
7 CAN communication circuit check
1) Disconnect connector s from BCM and ABS/ESP ®
control module.
2) Check CAN communication circuit between BCM and ABS/ESP ® control module for open, short and high
resistance.
Is each CAN communication circuit in good condition? Go to Step 8. Repair circuit.
8 CAN communication circuit check
1) Disconnect connectors of all control modules
communicating by means of CAN.
2) Check CAN communication circuit between control modules other than Step 7 for open, short and high
resistance.
Is each CAN communication circuit in good condition? Go to Step 9. Repair circuit.