B2426, B2427, B2428
Symptom: Fan control limited
Control voltage for ventilation fan, overload, shorted to ground or to Batt+
Fault symptom:
Fan control limited
Conditions
B2426: Control module output pin 20, overload.
B2427: Control module output pin 20, shorted to ground.
B2428: Control module output pin 20, shorted to battery positive
Diagnostic procedure
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1.
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Check fuse 12 and whether it is live.
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2.
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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.
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3.
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Plug a BOB into the ACC control module and check the voltage on pins 37 and 20 as follows:
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•
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Full fan
pin 37 approx. 0 volts
pin 20 approx. 5 volts
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•
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No fan
pin 37 approx. 12 volts
pin 20 approx. 0 volts
The fan can be controlled by means of the buttons on the ACC panel or with the ISAT.
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4.
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Check the wiring between the pins indicated below for continuity/shorting
ACC control module pin
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Connector H8-1 pin
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37
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6
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20
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8
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17
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5
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5.
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Change the fan control.
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6.
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Clear the diagnostic trouble codes. Continue with further measures as described in section
if the diagnostic trouble codes recur.
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