Suzuki Grand Vitara JB416 / JB420. Manual - part 290

7B-51 Air Conditioning System: 

DTC B1546: A/C Refrigerant Pressure Malfunction

S5JB0A7204042

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 using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Start A/C system for 1 min. or more.
5) Check DTC.

DTC Troubleshooting

10 Position sensor circuit check

1) Check air intake control actuator position sensor circuit 

referring to Step 1 to Step 6 and Step 11 to Step 12 of 
“DTC B1530: Air Intake Control Actuator (Position 
Sensor) and/or Its Circuit Malfunction”.

Is it in good condition?

Go to Step 11.

Repair circuit.

11 Air intake control actuator check

1) Check intake air control actuator referring to “Air Intake 

Control Actuator Inspection”.

Is it in good condition?

HVAC control module 
faulty.

Air intake control 
actuator faulty.

Step

Action

Yes

No

DTC Detecting Condition

Trouble Area

Outside temperature is more than specified value. However, refrigerant 
pressure is less than specified value.

• Refrigerant pressure sensor circuit
• Refrigerant pressure sensor
• Outside air temperature sensor 

circuit

• Outside air temperature sensor
• HVAC control module
• ECM
• BCM

Step

Action

Yes

No

1

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

OFF.

2) Turn ON ignition switch and clear DTC.
3) Ignition switch turned OFF position.
4) Turn ON ignition switch and check DTC.

Is there DTC B1546?

Go to Step 2.

Confirm that vehicle A/C 
system condition 
referring “A/C System 
Performance 
Inspection”, and 
recheck DTC.

2

Refrigerant pressure check
1) Connect scan tool to DLC with ignition switch OFF.
2) Ignition switch ON turned ON position.
3) Check refrigerant pressure displayed on scan tool.

Is it 340 kPa or more?

Go to Step 3.

Charge refrigerant and 
Confirm that vehicle A/C 
system condition 
referring to “A/C System 
Performance 
Inspection”. And then 
recheck DTC.

3

A/C system check
1) Confirm that vehicle A/C system condition referring to 

“A/C System Performance Inspection”.

Is A/C system in good condition?

Go to Step 4.

Repair and/or replace.

Air Conditioning System:  7B-52

DTC B1551: Serial Communication Circuit Malfunction

S5JB0A7204043

Wiring Diagram

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 using scan tool.
3) Check DTC.

4

Refrigerant pressure sensor check
1) Check refrigerant pressure sensor referring to “A/C 

Refrigerant Pressure Sensor and Its Circuit Inspection”.

Are refrigerant pressure sensor and/or its circuit in good 
condition?

Go to Step 5.

Repair circuit and/or 
replace refrigerant 
pressure sensor.

5

Outside temperature sensor check
1) Check outside temperature sensor referring to “Outside 

Air Temperature Sensor Inspection (If Equipped) in 
Section 9C”.

Is outside temperature sensor in good condition?

Replace HVAC control 
module.

Replace outside 
temperature sensor.

Step

Action

Yes

No

5V

G52-10

G30-5

YEL/RED

[A]

2

1

3

10

I5JB0A720029-01

[A]: HVAC control module connector “G52” (harness side view)

2. BCM

1. HVAC control module

3. Information display

DTC detecting condition

Trouble area

Serial communication signal is more than or less than specified value for 
specified time continuously.

• Serial communication line of BCM
• BCM
• Information display
• HVAC control module

7B-53 Air Conditioning System: 

DTC Troubleshooting

Step

Action

Yes

No

1

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

OFF.

2) Turn ignition switch ON and clear DTC referring to “DTC 

Clearance”.

3) Disconnect connector from information display with 

ignition switch turned OFF.

4) Turn ignition switch ON and check DTC referring to 

“DTC Check”.

Is there DTC B1551?

Go to Step 2.

Information display 
faulty.

2

Wire harness check
1) Disconnect connectors from BCM and HVAC control 

module.

2) Measure resistance between “G30-5” terminal of BCM 

connector and “G52-10” terminal of HVAC control 
module connector.

Is resistance below 5 

Ω

?

Go to Step 3.

“YEL/RED” wire open or 
high resistance circuit.

3

Wire harness check
1) Measure resistance between “G52-10” terminal of HVAC 

control module connector and vehicle body ground.

Is resistance infinity?

Go to Step 4.

“YEL/RED” wire shorted 
to ground circuit.

4

Wire harness check
1) Measure voltage between “G52-10” terminal of HVAC 

control module connector and vehicle body ground with 
ignition switch turned ON.

Is voltage 0 V?

Go to Step 5.

“YEL/RED” wire shorted 
to other circuit.

5

Serial communication signal check
1) Connect connectors to BCM and HVAC control module.
2) Using oscilloscope, check that serial communication 

signal at “G30-5” is outputted referring to “Voltage 
Check” in “Inspection of BCM and its Circuits in Section 
10B”.

Is serial communication signal outputted at “G30-5” terminal 
of BCM connector?

HVAC control module 
faulty.

BCM (included in 
junction block 
assembly) faulty.

Air Conditioning System:  7B-54

DTC B1552: Serial Communication Circuit Malfunction

S5JB0A7204044

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 using scan tool.
3) Check DTC.

DTC Troubleshooting

DTC B1553: CAN Communication Circuit Malfunction

S5JB0A7204045

DTC Detecting Condition and Trouble Area

DTC Troubleshooting

DTC detecting condition

Trouble area

Data received by HVAC control module from BCM is erroneous continuously. • BCM

• HVAC control module

Step

Action

Yes

No

1

Serial communication signal data check
1) Connect scan tool to DLC with ignition switch turned 

OFF.

2) Start engine and select “DATA LIST” mode on scan tool.
3) Check “Refrigerant Pressure”, “Vehicle Speed”, “Coolant 

Temp” and “Outside Air Temp” varies displayed on scan 
tool.

Is displayed each varies described varies in “Scan Tool 
Data”?

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

Go to Step 2.

2

Serial communication signal check
1) Connect connectors to BCM and HVAC control module.
2) Using oscilloscope, check that serial communication 

signal at “G30-5” is outputted referring to “Voltage 
Check” of “Inspection of BCM and its Circuits in Section 
10B”.

Is serial communication signal outputted at “G30-5” terminal 
of BCM connector?

HVAC control module 
faulty.

BCM (included in 
junction block 
assembly) faulty.

DTC detecting condition

Trouble area

HVAC control module receives error code from BCM continuously.

• CAN communication circuit
• BCM
• ECM
• HVAC control module

Step

Action

Yes

No

1

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

OFF.

2) Check ECM and BCM for DTC.

Is there DTC(s)?

Go to applicable DTC 
diag. flow.

Substitute a known-
good HVAC control 
module and recheck.