7B-56 Air Conditioning System: Automatic Type
DTC B1502: Inside Air Temperature Sensor Circuit Malfunction
[S]: Inside air temperature sensor signal circuit
[G]: Inside air temperature sensor ground circuit
DTC Detecting Condition and Trouble Area
Inside air temperature sensor signal voltage is higher than or lower than
specified value for specified time continuously.
When DTC B1503, B1504, B1511 and B1512 are indicated together, it is possible that sensor ground
circuit is open.
Was "Air Conditioning System Check" performed?
Wire harness check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from inside air temperature
sensor and HVAC control module.
3) Check for proper connection to each signal circuit
terminal and ground circuit terminal of inside air
temperature sensor and HVAC control module
4) If OK, check that inside air temperature sensor circuit is
• Wiring harness resistance of each inside air
temperature sensor signal circuit and ground circuit is
less than 3 Ω
• Insulation resistance between inside air temperature
sensor signal circuit and vehicle body ground is
• Circuit voltage of each inside air temperature sensor
signal circuit and ground circuit is 0 – 1 V with ignition
switch turned ON
Are they in good condition?
1. HVAC control module
2. Inside air temperature sensor
DTC Detecting Condition
Go to Step 2.
Go to Step 3.
3. To other sensors
• Inside air temperature sensor circuit
• Inside air temperature sensor
• HVAC control module
Go to "Air Conditioning
Inside air temperature
sensor signal circuit
and/or ground circuit are
open, short or high