Dtc B1503: Evaporator Temperature Sensor Circuit Malfunction - Suzuki SX4 Service Manual

Step
3 Inside air temperature sensor reference voltage check
1) Connect connector to HVAC control module with ignition
switch turned OFF.
2) Turn ignition switch to ON position.
3) Measure voltage between signal terminal and ground
terminal of inside air temperature sensor connector.
Is voltage 4.5 – 5.5 V?
4 Inside air temperature sensor check
1) Check inside air temperature sensor for performance
referring to "Inside Air Temperature Sensor Inspection:
Automatic Type".
Is it in good condition?

DTC B1503: Evaporator Temperature Sensor Circuit Malfunction

Wiring Diagram
2 [S]
WHT/BLK G20-9
ORN
3
[S]: Evaporator temperature sensor signal circuit
[G]: Evaporator temperature sensor ground circuit
DTC Detecting Condition and Trouble Area
Evaporator temperature sensor signal voltage is higher than or lower than
specified value for specified time continuously.
DTC Troubleshooting
NOTE
When DTC B1502, B1504, B1511 and B1512 are indicated together, it is possible that sensor ground
circuit is open.
Action
1
5V
14
30
ORN G20-24
[G]
DTC Detecting Condition
Air Conditioning System: Automatic Type 7B-57
Go to Step 4.
Substitute a known-
good HVAC control
module and recheck.
G20
13 12 11 10 9 8
29 28 27 26 25 24 23
1. HVAC control module
2. Evaporator temperature sensor
Yes
Substitute a known-
good HVAC control
module and recheck.
Replace inside air
temperature sensor.
7 6 5 4 3 2
22 21 20 19 18 17 16
3. To other sensors
Trouble Area
• Evaporator temperature sensor
circuit
• Evaporator temperature sensor
• HVAC control module
No
S7RW0A7224011
1
15
I7RW01722005-01