Dtc B1504: Sunload Sensor Circuit Malfunction - Suzuki SX4 Service Manual

7B-58 Air Conditioning System: Automatic Type
Step
1 Was "Air Conditioning System Check" performed?
2 Wire harness check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from evaporator temperature
sensor and HVAC control module.
3) Check for proper connection to each signal circuit
terminal and ground circuit terminal of evaporator
temperature sensor and HVAC control module
connectors.
4) If OK, check that evaporator temperature sensor circuit
is as follows.
• Wiring harness resistance of each evaporator
temperature sensor signal circuit and ground circuit is
less than 3 Ω
• Insulation resistance between evaporator temperature
sensor signal circuit and vehicle body ground is
Infinity
• Circuit voltage of each evaporator temperature sensor
signal circuit and ground circuit is 0 - 1 V with ignition
switch turned ON
Are they good condition?
3 Evaporator 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 evaporator temperature sensor connector.
Is voltage 4.5 – 5.5 V?
4 Evaporator temperature sensor check
1) Check evaporator temperature sensor for performance
referring to "Evaporator Temperature Sensor Inspection:
Automatic Type".
Is it in good condition?

DTC B1504: Sunload Sensor Circuit Malfunction

Wiring Diagram
2
[S]
ORN
3
[S]: Sunload sensor signal circuit
[G]: Sunload sensor ground circuit
Action
1
5V
PNK G20-25
ORN G20-24
[G]
1. HVAC control module
2. Sunload sensor
Go to Step 2.
Go to Step 3.
Go to Step 4.
Substitute a known-
good HVAC control
module and recheck.
14 13 12 11 10 9 8
30 29 28 27 26 25 24
Yes
Go to "Air Conditioning
System Check:
Automatic Type".
Evaporator temperature
sensor signal circuit
and/or ground circuit are
open, short or high
resistance.
Substitute a known-
good HVAC control
module and recheck.
Replace evaporator
temperature sensor.
G20
7 6 5 4 3
23 22 21 20 19 18 17
3. To other sensors
No
S7RW0A7224012
2 1
16 15
I7RW01722006-01