Automatic Climate Control, ACC

B2945





Sensor ground. Open circuit/short to B+

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

Conditions
The following conditions apply:
- Measured every 40 ms.
- Voltage on pins 36, 37, 38 or 39>0.4 V.





Diagnostic procedure

1. Checking the sensor's ground connection
- Turn the ignition key to ON.





- Unplug connector: Control module, ACC: (216).





- Connect a test amp between pins 1 and 36 on the female connector.

Does the test lamp light up?
YES
- Rectify lead with respect to short to B+.
- Go to step 5.
NO
- Go to step 2.





2. Checking sensor ground to pin 37
- Connect a test lamp between pins 1 and 37 on the female connector.

Does the test lamp light up?
YES
- Rectify lead with respect to short to B+.
- Go to step 5.
NO
- Go to step 3.





3. Checking sensor ground to pin 38
- Connect a test lamp between pins 1 and 38 on the female connector.

Does the test lamp light up?
YES
- Rectify lead with respect to short to B+.
- Go to step 5.
NO
- Go to step 4.





4. Checking sensor ground to pin 39
- Connect a test lamp between pins 1 and 39 on the female connector.

Does the test lamp light up?
YES
- Rectify lead with respect to short to B+.
- Go to step 5.
NO
- 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.