











Help me fix my air conditioning XENTRY says I need a new compressor. Do I need one?
i’m trying to do everything myself, but I want to make sure I’m not throwing parts at the car I have XENTRY star diagnostic and I can communicate with the air conditioning module using a cheap pass-through device.
it’s been really hot out lately and my wife has been on my *** to fix her air-conditioning. Any help is greatly appreciated.
Last edited by Heguli; Jul 17, 2023 at 02:57 PM.




1 - Does the shaft turns when the engine is running?
2 - Does the shaft turns by hand when the engine is NOT running?
(2) is needed if the answer to (1) is negative. You need test (2) since likely causes for a fail on test 1 is that the permanent coupling is broken. Why is the permanent coupling is broken? random failure or the compressor is seized. For the latter you need a new compressor; however, do NOT install a new compressor until you understand why it seized.
Sometimes the coupling itself fails, but the compressor is still if fair (not necessarily great) condition. However, if the compressor is seized, the coupling is torn to pieces to prevent a catastrophic situation under the hood.




When getting the compressor, be certain you are getting the correct one with or without the diode in the ECV. Some MB uses it some do not because it is already in the ECU.
Below taken from a W212 thread ( https://mbworld.org/forums/e-class-w...ml#post8699364)
Summary: MB AC systems with VariableDisplacement require a diode (let you read the why), but the diode can be installed in different places, i.e. fixed after the fact. So, there is quite a confusion in the aftermarket of ECV about MB requiring a diode since it is MODEL dependent. That is, if MB installed the diode in the ECU, it does not need a diode downstream. I guess once a platform with ECU that is designed w/o the diode, it must be added elsewhere
Last edited by JCM_MB; Jul 18, 2023 at 11:11 AM.
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For the M112 engine, I think there is enough space to take a picture of the compressor's label to see the specifications. I expect it to be one of the 2 in the photos I posted. Note they have different-sized pulleys. Do not go by the MB car model, i.e. E320 means nothing except that there are 2 different compressor models.
As I said earlier, if the shaft does not rotate with the engine, but it does manually (which is rare) there is a slight chance the inner guts of the pully are damaged. Here is a video on how to check the inner parts, is it trivial? depends if you have the tool to lock the pulley while you turn the nut out
Here is the tool (
If you remove the compressor from the vehicle (your call)
Last edited by JCM_MB; Jul 18, 2023 at 05:12 PM.




Those are the specs for that compressor model. Yellow dot or triangle means DIODE in the valve, so that should be fine. I would like to find out how you cross-reference the DCP17062 to the E-Class. The Denso catalog I have only shows the DCP17062 for GL 320/420/450, ML280/320/420/450 R280/320. Notice the pattern: X/W164 platform.
Last edited by JCM_MB; Aug 1, 2023 at 07:52 AM.
Those are the specs for that compressor model. Yellow dot or triangle means DIODE in the valve, so that should be fine. I would like to find out how you cross-reference the DCP17062 to the E-Class. The Denso catalog I have only shows the DCP17062 for GL 320/420/450, ML280/320/420/450 R280/320. Notice the pattern: X/W164 platform.
https://www.youtube.com/watch?v=eCyDO7uxrOY
Those are the specs for that compressor model. Yellow dot or triangle means DIODE in the valve, so that should be fine. I would like to find out how you cross-reference the DCP17062 to the E-Class. The Denso catalog I have only shows the DCP17062 for GL 320/420/450, ML280/320/420/450 R280/320. Notice the pattern: X/W164 platform.
https://www.youtube.com/watch?v=eCyDO7uxrOY




Since you have XEntry, you can monitor the temperature in the evaporator, and pressure of the refrigerant. I would also monitor the manifold low and high pressures.
1 - Turn ON the engine, and rev up to @1500RPM
2 - AC on MAXCOOL
3 - Monitor Evap Temp, fingers crossed it is @5C min, anything lower is bonus
4 - Monitor Refrigerant Pressure, @180+ PSI, @13 bar
5 - Check your ambient temperature sensor reports something reasonable, as well as the interior temperatures. There are two sensors: one near the ignition key (little screen), and on the overhead control panel.
6 - Check for codes on the sun sensors, and pollution sensor. If there are codes, the AC starts to misbehave. All of the sensors together try to control your comfort settings, i.e. AUTO mode.


