Automatic Climate Control, ACC

B1340





Solar sensor. open circuit/communication error

Fault symptoms
Perceived temperature in cabin too high or too low compared to the set temperature.

Conditions
The following conditions apply:
- Open circuit or communication error
- The solar sensor sends a continuous identification pulse 5V-OV-5V. The control module searches for identification pulses for periods of 440 ms. 5 consecutive periods without a pulse pattern is required to set a diagnostic trouble code.
- The diagnostic trouble code is deleted after the ignition has been turned on 20 times if the fault conditions have not been fulfilled.
- When the diagnostic trouble code is set, the control module uses a default value. The last valid value is used as a default value. When the ignition is turned on, 0 W/sq.m is used.

Diagnostic help
Check that a value is obtained from all 5 directions.





Diagnostic procedure

1. Checking the diagnostic trouble code
- Contact the ACC.

Is diagnostic trouble code B2945 displayed on the diagnostics tool?
YES
- Go to diagnostic trouble code B2945.
NO
- Go to step 2.





2. Checking sensor pulse feed
- Unplug connector: Solar sensor: (223).





- Connect a test lamp between pin 1 on the female connector and a reliable ground point.





- The test lamp should light.

Is the function correct?
YES
- Go to step 3
NO
- Rectify lead in question.
- Go to step 5.





3. Checking the sensor's ground connection
- Connect a test lamp between pins 1 and 4 on the female connector.





- The test lamp should light with a faint shine.

Is the function correct?
YES
- Go to step 4.
NO
- Rectify defect lead.
- Go to step 5.





4. Checking sensor signal lead
- Unplug connector: Control module, ACC: (216).





- Measure resistance.
- Red test lead: Solar sensor:2.





- Black test lead: Control module, ACC:17.
- Value should be 0 ohm.

Is the function correct?
YES
- Change : Solar sensor
- Go to step 5.
NO
- Rectify lead in question.
- Go to step 5.





5. Final check
- Delete diagnostic trouble codes in all Systems.





- Carry out a function check.
- Evaluate the function check.
- Check that the diagnostic trouble code does not recur.

Does the diagnostic trouble code recur?
YES
- See "Before changing a control module." Before Changing a Control Module

NO
- The steps taken to rectify the fault were correct.