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B1347

B1347

Blended-air sensor, shorting to ground

Conditions

B1347: Control module input pin 32, shorted to ground.


Diagnostic procedure

If diagnostic trouble code B1515 has been generated it should be dealt with first. See .


1. Connect the ISAT and obtain a "MIXED AIR SENSOR" readout. The voltage should be within 1-4 V and change when the selected indoor temperature is changed.

2. Unplug the 10-pin connector (H10-5) and check the voltage across connector pins 9 and 10. It should be about 4.5 - 5 V. If it is not, proceed to point 4.


3. Check the resistance directly across the blended-air sensor. It should vary with the temperature of the ambient air as shown in the table below. Fit a new blended-air sensor if the test result does not tally with the table. Clear the diagnostic trouble code and check that it is not generated afresh.





Minimum (kilo-ohms)

Maximum (kilo-ohms)

0 ° C

25.5

30.5

+ 10 ° C

16.6

19.7

+ 20 ° C

11.2

13.0

+ 30 ° C

7.7

8.8

+ 40 ° C

5.4

6.1






4. Unplug the ACC control module's connector. Connect a BOB to the wiring and check the leads for continuity and/or shorting as follows:



• across pin 14 of the ACC control module's connector and pin 9 of the sensor's connector H10-5

• across pin 32 of the ACC control module's connector and pin 10 of the sensor's connector H10-5.


Rectify any faulty lead in the wiring.

5. If the fault persists, proceed to section .