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Climate Control Unit location and AC Control Valve replacement question
Hello. I am having AC issues in my 2015 Mercedes C300 (with codes M014 and 919), which is only blowing warm air. I am trying to find the problem for a while now.
A member of this forum pointed out a possible ground circuit issue since most of the faulty sensors share same ground:
- B10/8 (Rear Center Air Vent Outlet Temperature Sensor) is showing -57 F
- B10/6 (Evaporator Temperature Sensor) is showing 108 F
- Scanner is reading a fault code B1113-15 (Temperature Sensor 'Right Footwell Vent Has A Malfunction. There Is A Short Circuit To Positive Or An Open Circuit)
- Scanner is reading a fault code B19A400: LIN bus 2 of the air conditioning system has a malfunction.
Could you advice on how to locate and test that circuit?
Also, there might be an issue with AC control valve. Is it replaceable in a W205 or it requires a new compressor?
Does anyone know the part number?
Hello. I am having AC issues in my 2015 Mercedes C300 (with codes M014 and 919), which is only blowing warm air. I am trying to find the problem for a while now.
A member of this forum pointed out a possible ground circuit issue since most of the faulty sensors share same ground:
- B10/8 (Rear Center Air Vent Outlet Temperature Sensor) is showing -57 F
- B10/6 (Evaporator Temperature Sensor) is showing 108 F
- Scanner is reading a fault code B1113-15 (Temperature Sensor 'Right Footwell Vent Has A Malfunction. There Is A Short Circuit To Positive Or An Open Circuit)
- Scanner is reading a fault code B19A400: LIN bus 2 of the air conditioning system has a malfunction.
Could you advice on how to locate and test that circuit?
Also, there might be an issue with AC control valve. Is it replaceable in a W205 or it requires a new compressor?
Does anyone know the part number?
Thank you
This is a great survey... you may not need a compressir or duty control valve if not proven guilty.
Plenty of other qualified reason for AAC module to veto service - Don't jump to conclude you need big ticket job: new evap coil
Your "evap 108C" is just saying system is at rest.
Rear vent -57c sounds like your scanner has limited support (showing random data!!) - FEEL FREE TO IGNORE THIS!
What has me concerned is the LIN Fault. I think this is upsetting your AAC module.
Diagram shows multiple LIN buses
Where does B2 command ???
If you want to gently back-probe the AAC fragile connector you will have access to everything in one single place.
Grab the opportunity to clean the painted GND near L+R footwell area.
Passenger side sensor got torned up in the course of servicing cabin filter. Have a looksee.
Last edited by CaliBenzDriver; 06-28-2024 at 12:03 AM.
I'll try to consolidate and summarize all my other posts.
Vehicle Information 2015 Mercedes C300 W205
Mileage: <50,000 miles
Location: Florida (high ambient temperatures)
Symptoms and main observation:
AC blowing warm air, no cold air.
Heating works fine; air gets warmer when temperature is turned up.
AC compressor starts spinning when turned on, stops when turned off.
Fan behind the radiator engages.
Low side pressure is high (105 PSI), high side pressure is low (110 PSI)
Both low and high stay pretty much the same with AC on and AC off
Most recent Launch scanner results at 2PM and at 10PM:
Additional diagnostic observation:
Compressor Clutch (A9/7y2): OPEN with AC off, CLOSED with AC on.
Coolant Circulation Pump (M13/5): Stays off with AC on and off (can be manually activated with no temperature change).
Rear Center Air Vent Sensor (B10/8): Constant -58°F, does not change.
Refrigerant Pressure (B12): 9.80 - 10.50 bar.
Evaporator Temperature Sensor (B10/6): 118-119°F.
Governor Power Consumption: Jumps from 0A to 24A with AC on, temperature increases from 165°F to 190°F.
Blower Motor RPM: Jumps from 0 RPM to 4540 RPM with AC ON.
Actuator Motor Positions: Some show 0 or -10000, indicating faults or misreads.
Coolant Temperature Sensor (B11/4): ~190°F.
EVAP System Vapor Pressure: -58.75 Pa.
Power Request to Component A9 (Refrigerant Compressor): high demand (98-100%) even at lowest setting, no refrigerant pressure increase.
Most of the faulty sensors share same ground
Error Codes:
B19A400: LIN bus 2 of the AC system malfunction. (did not show during automatic test but came up when I tested AC system manually)
P0597-00: Coolant thermostat electrical fault (cleared but occurred previously).
B1113-15: Right Footwell Vent Sensor malfunction (cleared but occurred previously).
Other most likely unrelated codes:
PO6DA00: Oil pump valve electrical fault.
U014787: Communication with "Head unit" malfunction.
U013200: Communication with "Suspension" malfunction.
C10C800: Warning from "Collision Prevention Assist".
SnapOn Scanner test a few weeks ago in cooler conditions, for comparison:
B10/6 (Evaporator Temp): 104.7°F.
B14 (Outside Temp): 89.5°F.
Outside Temperature: 83°F.
Interior Temp Sensor (N70b1): 98.4°F.
N70b1 Internal Fan: Running.
B10/35 (Left Footwell Vent Air Outlet Temp): 102.0°F.
B10/36 (Right Footwell Vent Air Outlet Temp): 103.1°F.
B10/31 (Left Side Air Vent Air Outlet Temp): 103.1°F.
B10/32 (Right Side Air Vent Air Outlet Temp): 104.0°F.
Coolant Temperature: 167°F.
Previous Voltage Issues, which might be related:
Battery load tested as good but dashboard showed "Stop Vehicle, Shift to P, Leave engine running" message.
Voltage regulator replaced, some codes cleared.
Battery replaced, dashboard message cleared.
Coolant refilled with G13 instead of G40 not too long before AC issue occured, not sure if this could be related
I also purchased a new thermostat due to P0597-00 code but I have not replaced it yet as the code cleared
I am including all fault codes which showed before replacing the battery and voltage regulator, along with clearing the codes, in spoiler box below
Spoiler
Overhead Control Panel
B181E-64: The Sensor For The Engine Hood Has A Malfunction. There is an implausible signal. - Stored.
B1F45-00: The Starter Battery Has Excessive Resistance. There Is A General Failure. - Stored.
B210C-13: The Power Supply Is Outside The Valid Range. There Is An Open Circuit. - Stored.
Air Conditioning
B107D-15: The Additional Coolant Pump Has A Malfunction. There Is A Short Circuit To Positive Or An Open Circuit. - Stored.
B10A2-07: The Actuator Motor For The Left Blend Air Flap Has A Malfunction. There Is A Mechanical Fault. - Stored.
Dimming Inside Rear View Mirror
(The same codes as listed under "Overhead Control Panel")
Headlamp - Left
U0132-00: Communication With Control Unit Suspension Has A Malfunction. There Is A General Failure. - Stored.
Panoramic Sliding Roof
U0168-87: Communication with the electronic ignition lock has a malfunction. The message is missing. - Stored.
Signal Acquisition Modules: SAM Module - Front
(The same codes as listed under "Overhead Control Panel")
Signal Acquisition Modules: SAM Module - Rear
B1F25-15: The Output For Warning / Ambient Lamp Lift Gate Has A Malfunction. There Is A Short Circuit To Positive Or An Open Circuit. - Stored.
B1F38-13: The Output For Switch And Controls Illumination Emergency Trunk Lid Release Has A Malfunction. There Is An Open Circuit. - Stored.
Steering Column Module
P172A-29: The Direct Select Lever Has A Malfunction. The Signal Is Invalid. - Stored.
Engine
P0597-00: The coolant thermostat has an electrical fault or open circuit. There Is A General Failure. - Stored.
P06DA-00: The actuation of the valve of the oil pump in the combustion engine has an electrical fault or open circuit. There Is A General Failure. - Current, Pending.
P0563-00: The On-Board Power Supply Voltage Is Too High. There Is A General Failure. - Stored.
Antilock Brakes
C100B-77: The Electric Parking Brake Has A Malfunction. The commanded position cannot be reached. - Stored.
C100B-FA: The Electric Parking Brake Has A Malfunction. - Stored.
C100B-FF: The Electric Parking Brake Has A Malfunction. - Current, Pending, Stored.
Electronic Power Steering
B210F-00: Input 'Circuit 30' Has A Malfunction. There Is A General Failure. - Stored.
Every necessary condition is present for compressor to pump. Right now it spins without building a head pressure.
Your compressor governor is jammed. Replace it
Thank you so much! I really appreciate it!!
Just want to clarify, by governor you mean the AC control valve (solenoid), correct?
Do you know if it's replaceable or if I need to replace the whole compressor?
Upon doing some reading, I found that a faulty AC pressure switch could also be causing the same problem. Is that a possibility in my case or it's definitely a mechanical jam?
Just want to clarify, by governor you mean the AC control valve (solenoid), correct?
Do you know if it's replaceable or if I need to replace the whole compressor?
Upon doing some reading, I found that a faulty AC pressure switch could also be causing the same problem. Is that a possibility in my case or it's definitely a mechanical jam?
Your survey shows the compressor is running and pressures remain equalized: no effective pumping!
Yes, it's the compressor pressure solenoid at the rear (not clutch solenoid at the front). It controls the compressor tilt plate with a pulsed voltage.
Your are reporting your B12 pressure sensor showing 10Bar. This tells us the sensor is working and the charge level is fine. However if you can get a good quality replacement sensor, I would replace it preventively since you will have the circuit depressurized anyway.
The cheap service ports Schrader valves are classic leakers once disturbed... replace them too.
I will have that replaced.
Just having a hard time finding the right part number for the compressor valve (the compressor # is most likely A0008303002) and the schrader port valve core (the ones available online do not show fitment with 2015 model). I sent a message to the manufacturers.
I also purchased an expansion valve (OEM from Four Seasons) since I thought that it might be faulty. Would you replace it or leave the genuine one in, since it not causing any problems?
I will have that replaced.
Just having a hard time finding the right part number for the compressor valve (the compressor # is most likely A0008303002) and the schrader port valve core (the ones available online do not show fitment with 2015 model). I sent a message to the manufacturers.
I also purchased an expansion valve (OEM from Four Seasons) since I thought that it might be faulty. Would you replace it or leave the genuine one in, since it not causing any problems?
You know that's a good question.
If you have a good quality part on hand and the refrigerant is going to be evacuated ok. Right now its guaranteed not to be causing compressor upset.
06-27-2024, 02:00 PM
