Suzuki Grand Vitara JB416 / JB420 (ESP model). Service manual - part 103

10B-14 Body Electrical Control System:

DTC U1101 (No. 1101): Lost communication with TCM

S5JB0EA204015

Wiring Diagram
Refer to “DTC U1073 (No. 1073): Control Module Communication Bus Off”.

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

BCM can not receive CAN data from TCM (A/T
model) for longer than specified time
continuously.

• CAN communication circuit
• BCM
• TCM (A/T model)

Step

Action

Yes

DTC check of BCM

Is DTC U1101 (No. 1101) and DTC U1073 (No. 1073)
detected together?

Go to “DTC U1073 (No.
1073): Control Module
Communication Bus
Off”.

Go to Step 2.

DTC check of TCM
1) Check TCM for DTC.

Is DTC P1774 detected?

Go to “DTC P1774:
CAN Communication
Bus Off in Section 5A”.

Go to Step 3.

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 U1101 (No. 1101) detected?

Go to Step 4.

Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section 00
in related manual”.

CAN communication circuit check
1) Disconnect connectors from BCM and TCM.
2) Check CAN communication circuit for open, short and

high resistance.
• Between TCM and BCM

Is each CAN communication circuit in good condition?

Go to Step 5.

Repair circuit.

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.

DTC check of ECM
1) Connect connectors of disconnected control modules

communicating by means of CAN.

2) Check ECM for DTC.

Is DTC U1101 detected?

Check TCM power and
ground circuit. If circuit
is OK, substitute a
known-good TCM and
recheck.

Go to Step7.

Body Electrical Control System: 10B-15

DTC check of BCM
1) Turn ignition switch to OFF position.
2) Disconnect connector of any one of control module other

than BCM.

3) Recheck BCM for DTC.

Is DTC U1101 (No.1101) detected?

Disconnect connectors
of control modules other
than the one whose
connector is
disconnected in Step 2)
one by one and check
that DTC U1101 is
detected by BCM each
time connector is
disconnected. When
DTC U1101 is not
detected by BCM while
checking in this way, go
to description under
“NO” below. If DTC
U1101 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.

Step

Action

Yes

10B-16 Body Electrical Control System:

DTC U1144 (No. 1144): Lost Communication with Keyless Start Control Module

S5JB0EA204016

Wiring Diagram
Refer to “DTC U1073 (No. 1073): Control Module Communication Bus Off”.

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

BCM can not receive data sent by CAN from keyless start
control module for longer than specified time continuously.

• CAN communication circuit
• Keyless start control module
• BCM

Step

Action

Yes

DTC check of BCM

Is DTC U1144 (No. 1144) and DTC U1073 (No. 1073)
detected together?

Go to “DTC U1073 (No.
1073): Control Module
Communication Bus
Off”.

Go to Step 2.

DTC check of keyless start control module
1) Check keyless start control module for DTC.

Is DTC No. 33 detected?

Go to “DTC No. 33:
Control Module
Communication Bus Off
in Section 10E”.

Go to Step 3.

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 U1144 (No. 1144) detected?

Go to Step 4.

Intermittent trouble.
Check for intermittent
referring to “Intermittent
and Poor Connection
Inspection in Section 00
in related manual”.

CAN communication circuit check
1) Turn ignition switch to OFF position.
2) Disconnect connectors of BCM and keyless start control

module communicating by means of CAN.

3) Check CAN communication circuit between BCM and

keyless start control module for open, short and high
resistance.

Is each CAN communication circuit in good condition?

Go to Step 5.

Repair circuit.

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.

Key indicator lamp operation check
1) Connect connectors of disconnected control modules

communicating by means of CAN.

2) Push ignition knob switch of steering lock unit.

Does key indicator lamp turn ON?

Go to Step 7.

Check keyless start
control module power
and ground circuit. If
circuit is OK, substitute
a known-good keyless
start control module and
recheck.

Body Electrical Control System: 10B-17

DTC check of BCM
1) Disconnect connector of any one of control module other

than BCM.

2) Recheck BCM for DTC.

Is DTC U1144 (No.1144) detected?

Disconnect connectors
of control modules other
than the one whose
connector is
disconnected in Step 1)
one by one and check
that DTC U1144 is
detected by BCM each
time connector is
disconnected. When
DTC U1144 is not
detected by BCM while
checking in this way, go
to description under
“NO” below. If DTC
U1144 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 1). If circuit is OK,
substitute a known-
good control module
disconnected in Step 1)
and recheck.

Step

Action

Yes

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