Dtc B1546: A/C Refrigerant Pressure Malfunction - Suzuki SX4 Service Manual

Step
3 Battery voltage supply circuit check
1) Disconnect connector from HVAC control module with
ignition switch turned OFF.
2) Check for proper connection to back-up power supply
circuit terminal of HVAC control module connector.
3) If OK, measure voltage between back-up power supply
circuit terminal of HVAC control module connector and
vehicle body ground.
Is voltage 10 – 14 V?

DTC B1546: A/C Refrigerant Pressure Malfunction

DTC Detecting Condition and Trouble Area
• A/C refrigerant pressure sensor signal voltage is lower than specified value
even though outside air temperature is higher than specified value for
specified time continuously.
• Insufficient refrigerant in A/C system
DTC Troubleshooting
Step
1 Was "Air Conditioning System Check" performed?
2 DTC check
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ignition switch to ON position and check DTC in
BCM.
Is DTC B1141 or B1142 (BCM) detected?
3 DTC check
Check DTC in ECM.
Is DTC P0532 or P0533 detected?
4 A/C refrigerant pressure and outside air temperature
data check
1) Start engine and select "DATA LIST" mode on scan tool.
2) Check "Refrigerant Pressure" and "Outside Air Temp"
displayed on scan tool.
Are values of A/C refrigerant pressure sensor and outside air
temperature within specified ranges indicated in "Scan Tool
Data"?
Action
DTC detecting condition
Action
Air Conditioning System: Automatic Type 7B-67
Yes
Substitute a known-
good HVAC control
module and recheck.
• Insufficient of refrigerant
• A/C refrigerant pressure sensor
• Outside air temperature sensor
• HVAC control module
Yes
Go to Step 2.
Go to applicable DTC
diag. flow.
Go to applicable DTC
diag. flow.
Substitute a known-
good HVAC control
module and recheck.
No
Back-up power supply
circuit is open or
shorted to ground.
S7RW0A7224019
Trouble area
No
Go to "Air Conditioning
System Check:
Automatic Type".
Go to Step 3.
Go to Step 4.
Check the amount of
refrigerant and system
for leaks.