AUTO A/C DIAGNOSIS
TSB Revision
AUTOMATIC AIR CONDITIONING
55B-9
STEP 1. Using scan tool MB991502, check data list item 13:
Ambient air temperature sensor.
Item 13: Ambient air temperature sensor
OK: The outside air temperature and indicated temperature on
scan tool MB991502 are almost equal.
Q: Are the outside air temperature and temperature
displayed on scan tool MB991502 almost equal?
YES : It can be assumed that this malfunction is
intermittent. (Refer to GROUP 00 - How to Cope with
Intermittent Malfunction
P.00-6
.)
NO : Go to Step 2.
STEP 2. Check the outside air temperature sensor.
Disconnect outside air temperature sensor connector A-29, and
measure the resistance between terminal numbers 1 and 2.
Measure the resistance between the sensor terminals under at
least two temperatures.
NOTE: The temperature conditions at the check should be
within the range shown in the characteristic diagram.
Q: Is the check result normal?
YES : Go to Step 3.
NO : Replace the outside air temperature sensor. Then go
to Step 5.
AC204166
CONNECTOR : A-29
AP
A-29(B)
A-29(B)
1
2
HARNESS
SIDE
AC001680AB
OUTSIDE AIR
TENPERATURE SENSOR
REGISTANCE k
Ω
10
8
6
4
2
0
-10
0
10
20
30
40
(14) (32)
(50)
(68)
(86) (104)
TEMPERATURE ˚C (˚F)