B2428

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DTC B2426, B2427, B2428
Control voltage for ventilation fan, overload, shorted to ground or to Batt+.

Fault symptom
Fan control limited.

Conditions
132426: Control module output pin 20, overload.
132427: Control module output pin 20, shorted to ground.
132428: Control module output pin 20, shorted to battery positive.

Diagnostic procedure
1. Check fuse 12 and whether it is live.
2. If diagnostic trouble code B1355 has been generated it should be dealt with first. Then clear the trouble codes. Continue fault diagnosis if they recur.
3. Plug a BOB into the ACC control module and check the voltage on pins 37 and 20 as follows:
- Full fan
pin 37 - approx. 0 V
pin 20 - approx. 5 V
- No fan
pin 37 - approx. 12 V
pin 20 - approx. 0 V
The fan can be controlled by means of the buttons on the ACC panel or with the ISAT.
4. Check the wiring between the pins indicated in table below for continuity/shorting.





5. Change the fan control.
6. Clear the trouble codes. Continue with the diagnostic procedure as described in "Before Changing A Control Module" if the trouble codes recur. Testing and Inspection