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