Suzuki Grand Vitara JB627. Manual — part 62

1A-197 Engine General Information and Diagnosis:

DTC U0140: Lost Communication with Body Control Module

S6JB0B1104083

Wiring Diagram
Refer to “DTC U0073: Control Module Communication Bus Off”.

DTC Detecting Condition and Trouble Area

14 DTC check

1) Disconnect connector from steering angle sensor

(ESP

® model) with ignition switch turned OFF.

2) Check ECM for DTC.

Is there DTC U0121?

Go to Step 15.

CAN communication
circuit wire between
steering angle sensor
and CAN circuit junction
connector is open or
high resistance. If wires
are OK, check steering
angle sensor power and
ground circuits. If
circuits are OK,
substitute a known-
good steering angle
sensor and recheck.

15 DTC check

1) Disconnect connectors from all control modules (ECM,

TCM (A/T model), BCM, ABS or ESP

® control module,

4WD control module (if equipped), keyless start control
module (if equipped), combination meter, steering angle
sensor (ESP

® model)) with ignition switch turned OFF.

2) Check that CAN communication circuit is as follows.

• ALL wire harness resistance of CAN communication

circuit is less than 1

Ω between each control module.

• Insulation resistance between CAN communication

circuit wires is infinity at each control module
connector.

• Insulation resistance between each CAN

communication circuit wire and vehicle body ground is
infinity at each control module connector.

• Circuit voltage of CAN communication circuit is 0 V

with ignition switch turned ON.

Are they in good condition?

Go to Step 16.

Repair or replace
defective CAN
communication circuit.

16 Warning light check

1) Connect connectors to all control modules

communicating by CAN.

2) Turn ignition switch ON.

Is ABS or ESP

®

warning light light up?

Substitute a known-
good ABS or ESP

®

control module and
recheck.

Substitute a known-
good ECM and recheck.

Step

Action

Yes

No

DTC detecting condition

Trouble area

Reception error of communication data for BCM is detected for longer
than specified time continuously.
(1 driving cycle detection logic)

• CAN communication circuit
• Combination meter
• Keyless start control module (if equipped)
• BCM
• 4WD control module (if equipped)
• ABS or ESP

® control module

• TCM (A/T model)
• Steering angle sensor (ESP

® model)

• ECM

Engine General Information and Diagnosis: 1A-198

DTC Confirmation Procedure

1) Clear DTC referring to “DTC Clearance” in this section.
2) Start engine and run it for 1 min. or more.
3) Check DTC referring to “DTC Check”.

DTC Troubleshooting

NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions for DTC Troubleshooting”.

Step

Action

Yes

No

1

Was “Engine and Emission Control System Check”
performed?

Go to Step 2.

Go to “Engine and
Emission Control
System Check”.

2

DTC check
1) Connect scan tool to DLC with ignition switch turned

OFF.

2) Check for all control modules (ECM, TCM (A/T model),

BCM, ABS or ESP

® control module, 4WD control

module (if equipped), keyless start control module (if
equipped), combination meter, steering angle sensor
(ESP

® model)) for DTC(s) other than CAN

communication DTCs.

Is there any DTC(s) other than CAN communication DTC(s)
at each control module (other than DTC U0073, U0100,
U0101, U0121, U0140, U1073, U1100, U1101, U1121,
U1126, U1139, U1140, U1144)?

Go to applicable DTC
diag. flow.

Go to Step 3.

3

DTC check

Is DTC U0140 and U0073 detected together?

Go to “DTC U0073:
Control Module
Communication Bus
Off”.

Go to Step 4.

4

ECM, ABS or ESP

® control module and BCM connector

check
1) Check for proper connection at each ECM, ABS or

ESP

® control module and BCM connector terminals with

ignition switch turned OFF.

2) If connections are OK, recheck ECM for DTC with

engine running.

Is there DTC U0140?

Go to Step 5.

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

5

ECM power and ground circuit check
1) Check ECM power and ground circuits referring to “ECM

Power and Ground Circuit Check”.

Are they in good condition?

Go to Step 6.

Repair ECM power and/
or ground circuits.

6

DTC check in BCM
1) Check DTC U1073 in BCM.

Is it indicated?

Go to “DTC U1073 (No.
1073): Control Module
Communication Bus Off
in Section 10B”.

Go to Step 7.

1A-199 Engine General Information and Diagnosis:

7

DTC check
1) Disconnect connector from BCM and ECM.
2) Check that CAN communication circuit is as follows.

• Circuit resistance of CAN communication circuit is

less than 1

Ω between ECM connector and BCM

connector.

Is it in good condition?

Go to Step 9.

Go to Step 8.

8

Circuit check
1) Measure resistance at following connector terminals.

• Between “WHT/BLU” terminal and “WHT” terminal of

ABS or ESP

® control module connector.

• Between “WHT/RED” terminal and “RED” terminal of

ABS or ESP

® control module connector.

Is measured resistance below 1

Ω

?

CAN communication
circuit wire between
BCM and ECM
connector is open or
high resistance.

Substitute a known-
good ABS or ESP

®

control module and
recheck.

9

DTC check
1) Connect connectors to BCM and ECM with ignition

switch turned OFF.

2) Disconnect connectors from TCM (A/T model) with

ignition switch turned OFF.

3) Check ECM for DTC.

Is there DTC U0140?

Go to Step 10.

CAN communication
circuit wire between
TCM and CAN circuit
junction connector is
open or high resistance.
If wires are OK, check
TCM power and ground
circuits. If circuits are
OK, substitute a known-
good TCM and recheck.

10 DTC check

1) Disconnect connector from keyless start control module

(if equipped) with ignition switch turned OFF.

2) Check ECM for DTC.

Is there DTC U0140?

Go to Step 11.

CAN communication
circuit wire between
keyless start control
module and CAN circuit
junction connector is
open or high resistance.
If wires are OK, check
keyless start control
module power and
ground circuits. If
circuits are OK,
substitute a known-
good keyless start
control module and
recheck.

11 DTC check

1) Disconnect connector from combination meter with

ignition switch turned OFF.

2) Check ECM for DTC.

Is there DTC U0140?

Go to Step 12.

CAN communication
circuit wire between
combination meter and
CAN circuit junction
connector is open or
high resistance. If wires
are OK, check
combination meter
power and ground
circuits. If circuits are
OK, substitute a known-
good combination meter
and recheck.

Step

Action

Yes

No

Engine General Information and Diagnosis: 1A-200

12 DTC check

1) Disconnect connector from 4WD control module (if

equipped) with ignition switch turned OFF.

2) Check ECM for DTC.

Is there DTC U0140?

Go to Step 13.

CAN communication
circuit wire between
4WD control module
and CAN circuit junction
connector is open or
high resistance. If wires
are OK, check 4WD
control module power
and ground circuits. If
circuits are OK,
substitute a known-
good 4WD control
module and recheck.

13 DTC check

1) Disconnect connector from steering angle sensor

(ESP

® model) with ignition switch turned OFF.

2) Check ECM for DTC.

Is there DTC U0140?

Go to Step 14.

CAN communication
circuit wire between
steering angle sensor
and CAN circuit junction
connector is open or
high resistance. If wires
are OK, check steering
angle sensor power and
ground circuits. If
circuits are OK,
substitute a known-
good steering angle
sensor and recheck.

14 DTC check

1) Disconnect connectors from all control modules (ECM,

TCM (A/T model), BCM, ABS or ESP

® control module,

4WD control module (if equipped), keyless start control
module (if equipped), combination meter, steering angle
sensor (ESP

® model)) with ignition switch turned OFF.

2) Check that CAN communication circuit is as follows.

• ALL wire harness resistance of CAN communication

circuit is less than 1

Ω between each control module.

• Insulation resistance between CAN communication

circuit wires is infinity at each control module
connector.

• Insulation resistance between each CAN

communication circuit wire and vehicle body ground is
infinity at each control module connector.

• Circuit voltage of CAN communication circuit is 0 V

with ignition switch turned ON.

Are they in good condition?

Go to Step 15.

Repair or replace
defective CAN
communication circuit.

15 Vehicle spec check

Is vehicle equipped with A/T?

Go to Step 16.

Go to Step 17.

16 DTC check in TCM (A/T model)

1) Connect connectors to all control modules with ignition

switch turned OFF.

2) Check DTC U0140 in TCM (A/T model).

Is it indicated?

Go to Step 17.

Substitute a known-
good ECM and recheck.

Step

Action

Yes

No