Mazda CX-7 2007 Workshop Manual page 1115

DTC B1255, B1257
DTC B1255,
Ambient temperature sensor system
B1257
• Ambient temperature sensor malfunction
POSSIBLE
• Open or short circuit in wiring harness between climate control unit and ambient temperature sensor
CAUSE
Diagnostic Procedure
STEP
• Inspect the ambient temperature sensor. (See 07-
1
40-24 AMBIENT TEMPERATURE SENSOR
INSPECTION.)
• Is it normal?
• Disconnect the climate control unit connector and
2
the ambient temperature sensor connector.
• Is there an open circuit in the wiring harness
between the following terminals of the climate
control unit and the ambient temperature sensor?
— L— B
— C— A
• Is there a short circuit to ground in the wiring
3
harness between climate control unit terminal L
and ambient temperature sensor terminal B?
• Turn the ignition switch to the ON position.
4
• Inspect the voltage at the following climate control
unit terminal (wiring harness-side).
— Terminal L (ambient temperature sensor input
signal)
• Is the voltage normal? (Approx. 5 V)
CLIMATE CONTROL UNIT CONNECTOR
W U S Q O
V T R P
X
End Of Sie
ON-BOARD DIAGNOSTIC
INSPECTION
M K I G E C A
N L J H D
F B
Yes Go to the next step.
No Replace the ambient temperature sensor. (See 07-40-
24 AMBIENT TEMPERATURE SENSOR REMOVAL/
INSTALLATION.)
Yes Repair the wiring harness.
No Go to the next step.
Yes Repair the wiring harness.
No Connect the climate control unit connector, then go to
the next step.
Yes The system is normal at present. (Clear the malfunction
from the memory.)
No Inspect the connection of the climate control unit
connector. (See 07-40-13 CLIMATE CONTROL UNIT
INSPECTION [FULL-AUTO AIR CONDITIONER].)
AMBIENT TEMPERATURE SENSOR CONNECTOR
B
id070200800600
ACTION
A
07-02–5
07-02