Car model and year: 2007 Mercedes ML350
Symptom: AC just stopped working, but the fan went on high.
What I tried to do:
Went to have it checked and was told that there was an obstruction on the system and Compressor no good. So I replaced the Compressor, Dryer, Expansion Valve, AC Pressure Sensor, Ambient Sensor, and replaced all seals. Did a 2-hour vacuum, let sit for 1 hour to see if had any leaks. But when I’m trying to charge the system, after the 2nd 12 oz can, it doesn’t want to accept any more refrigerant as it seems that the Compressor is not activating. Checked the voltage and there are only 4.2 volts. I replaced the Climate Control Switch w/another used one to check, but still all the same.
What should do next?
When there is a problem in the A/C system, the A/C Control Module will prevent the compressor to operate. The code/s must be read to see what the problem is.
After replacing the component, according to the code #, the code must be erased and then the A/C compressor will then be operated.
You must own your own Mercedes scanner for this problem and any other future problem that you might have.
Autel MaxiDiag MD808 Pro is a decent scanner for Benz car makes and any other cars when you need it.
Full list of fault codes and events:
9001 Control unit N22 (AAC [KLA] control and operating unit) is defective.
9002 B10/6 (Evaporator temperature sensor): Short circuit to ground
9003 B10/6 (Evaporator temperature sensor): Open circuit
9006 Component A9 (AC compressor) has a Short circuit.
9007 Component A9 (AC compressor) has an Open circuit.
900A B12 (Refrigerant pressure sensor): Short circuit to ground
900B B12 (Refrigerant pressure sensor): Open circuit
900C B12 (Refrigerant pressure sensor): Supply voltage > 5.1 V
900D B12 (Refrigerant pressure sensor): Supply voltage < 4.9 V
9101 B10/33 (Left center outlet temperature sensor): Short circuit to ground
9102 B10/33 (Left center outlet temperature sensor): Open circuit
9103 B10/34 (Right center outlet temperature sensor): Short circuit to ground
9104 B10/34 (Right center outlet temperature sensor): Open circuit
9105 B10/35 (Left footwell temperature sensor): Short circuit to ground
9106 B10/35 (Left footwell temperature sensor): Open circuit
9107 B10/36 (Right footwell temperature sensor): Short circuit to ground
9108 B10/36 (Right footwell temperature sensor): Open circuit
9109 B10/31 (Left side outlet temperature sensor): Short circuit to ground
910A B10/31 (Left side outlet temperature sensor): Open circuit
910B B10/32 (Right side outlet temperature sensor): Short circuit to ground
910C B10/32 (Right side outlet temperature sensor): Open circuit
910D B10/7 (Center rear interior temperature sensor): Short circuit to ground
910E B10/7 (Center rear interior temperature sensor): Open circuit
9201 B14 (Ambient temperature display temperature sensor): Short circuit to ground
9203 B32 (Sun sensor): Short circuit to ground
9204 B32 (Sun sensor): Open circuit
9207 Internal fault in component N22/7b1 (In-car temperature sensor):
9303 M13 (Heating water circulation pump): Short circuit to ground
9304 M13 (Heating water circulation pump): Open circuit
930B R1 (rear window defroster) : Fault
9401 M2/6 (Left blending air flap actuator): LIN bus communication error
9402 M2/7 (Right blending air flap actuator): LIN bus communication error
9403 M2/12 (Rear shutoff flap positioning motor): LIN bus communication error
9404 M16/23 (Air flap actuator motor, left center vent): LIN bus communication error
9406 M2/15 (Left and right footwell flaps actuator): LIN bus communication error
9408 M2/16 (Left and right defroster flaps actuator): LIN bus communication error
9501 M2/5 (Fresh and recirculated air flaps actuator): LIN bus communication error
9503 M2/21 (Rear air distribution flap positioning motor): LIN bus communication error
9601 LIN bus error: Not within the valid voltage range
9602 LIN bus error: Ground potential outside the valid range
9606 Blower ( Front ): LIN bus communication error
9607 Booster blower: There is a short circuit to ground or the line for the readback voltage
has an open circuit.
9608 Booster blower: There is an open circuit or the line for the readback voltage has a short
circuit to ground.
960A LIN bus error: BUS communication not possible
9801 Button ‘AUTO’ sticks.
9803 Button ‘Defrost mode (DEFROST)’ sticks.
9804 Button ‘Recirculated air’ sticks.
9805 Button ‘Rear window defroster’ sticks.
9806 Button ‘AC OFF’ sticks.
9807 Button ‘Switching off the rear air conditioning’ sticks.
9808 Button ‘OFF’ sticks.
9809 Button ‘Airflow up’ sticks.
980A Button ‘Air distribution via center outlets’ sticks.
980B Button ‘Air distribution in footwell’ sticks.
980F Button ‘Increase of blower output’ sticks.
9810 Button ‘Reducing the blower output’ sticks.
Event 900E Local undervoltage at circuit 30 (voltage < 9 V)
Event 900F Local overvoltage at circuit 30 (voltage > 16 V)
Event 9701 Fault in CAN communication with control unit N73 (EIS [EZS] control unit).
Event 9702 Fault in CAN communication with control unit CGW.
Event 9703 Fault in CAN communication with control unit N10 (Front SAM control unit).
Event 9704 Fault in CAN communication with control unit A1 (Instrument cluster).
Event 9705 Fault in CAN communication with control unit N72/2 (RCP control module).
Event 9706 Fault in CAN communication with control unit N10/8 (Rear SAM control unit).
Event 9707 Fault in CAN communication with control unit N69/1 (Left front door control unit).
Event 9708 Fault in CAN communication with control unit N69/2 (Right front door control
unit).
Good luck!
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https://www.obd2shop.co.uk/wholesale/autel-maxidag-md808-pro-full-system-diagnostic-tool.html
