Dtc B1503 (No.03): A/C Evaporator Air Temperature Sensor And/Or Its Circuit Malfunction - Suzuki Liana RH413 Service Manual

Step
4 1) With ignition switch ON position, check voltage between
"ORN/BLK" wire terminal and "BLK/RED" wire terminal
at inside air temperature sensor connector.
Is voltage about 3.5 V?
5 1) Check inside air temperature sensor referring to "Inside
Air Temperature Sensor Inspection".
Is inside air temperature sensor normal?

DTC B1503 (No.03): A/C Evaporator Air Temperature Sensor and/or its Circuit Malfunction

Wiring Diagram
2
1. HVAC control module
DTC Detecting Condition and Trouble Area
• Signal from A/C evaporator temperature sensor is less than the specified
(0.7 V). (A/C evaporator temperature is less than –70 °C, –94 °F.)
• Signal from A/C evaporator temperature sensor is more than the specified
(3.3 V). (A/C evaporator temperature is more than 107 °C, 224.6 °F.)
DTC Troubleshooting
Step
1 1) Turn ignition switch OFF, and then disconnect A/C
evaporator temperature sensor connector referring to "A/
C Evaporator Outlet Air Temperature Sensor Removal
and Installation".
2) Turn ignition switch ON, and then check voltage
between "WHT/BLK" wire terminal at A/C evaporator
temperature sensor connector and body ground.
Is voltage about 3.5 V?
2 1) Turn ignition switch OFF, and then disconnect HVAC
control module connector referring to "HVAC Control
Module Removal and Installation in Section 7A".
2) Check resistance between "WHT/BLK" wire terminal at
A/C evaporator temperature sensor connector and
"WHT/BLK" wire terminal at HVAC control module
connector.
Is resistance less than 1 M
Action
G77-30
WHT/BLK
BLK/RED G77-9
2. A/C evaporator air temperature sensor
DTC Detecting Condition
Action
Ω
?
Air Conditioning System: Automatic Type 7B-56
Go to Step 5.
HVAC control module
faulty.
1
5V
12
3. HVAC control module connector "G77" (viewed from harness side)
Go to Step 4.
Go to Step 3.
Yes
"BLK/RED" wire open,
poor connection of
"BLK/RED" wire
terminal at HVAC
control module
connector, and/or HVAC
control module faulty.
Inside air temperature
sensor faulty.
3
9
Trouble Area
• "WHT/BLK" and/or "BLK/RED" wire
faulty
• A/C evaporator air temperature
sensor faulty
• HVAC control module faulty
Yes
Go to Step 2.
"WHT/BLK" wire open
or high resistance.
No
S3RH0A7224013
I3RH0A722009-01
No