I have a 2008 Vauxhall Astra 1.9 CDTI 8V (Z19DT engine) Elite (it has Climate Control)

Today the AC suddenly stopped blowing cold air, it worked fine yesterday so I took my OPCOM unit to read the codes and there are no trouble codes, so I checked the live data and took a freeze frame.

It has this to say about the AC in the live data/freeze frame:

A/C Information Switch: Active
A/C Cutoff Mode (Air Conditioning): System OK
A/C Pressure (Air Conditioning): 720 kPa
A/C Pressure (Air Conditioning): 1.1V (raw sensor 
A/C Relay (Air Conditioning): Active

System OK has to mean there's gas in the system, if there was no gas it'd say Underpressure...

Anyone have any idea whats wrong with my AC? The system was regassed 2 months ago so I have no idea what's wrong. Vauxhall say the pressure should range from 320kPa to 2800kPa so there is certainly gas in the system.

Uploaded the entire live data readout if anyone wants to take a look

What else could be wrong?

  • Your compressor, if it's the one with the clutch, should be the 4752 WM one (google for "delphi wm compressor" or "delphi 4752" and look for pictures). 9393 DQ2 is instead a clutchless compressor.
    – Al_
    Commented Jul 31, 2018 at 17:47
  • By the way, a little tip: always wondered what "PAG OIL 9986181" on these compressors means? Well, if you look at the label of a Delphi 9014 compressor (the ones featured on R50/R53 Minis; it's a CVC compressor equivalent to the one we're talking about, just different refrigerant ports and mounts), it says "PAG OIL 9986181" and then "(accept ND8 for refill)". See for yourself. Well, ND8 (NipponDenso Oil #8) is nothing but double end capped PAG oil of ISO 46 viscosity grade. So 9986181 apparently calls for this kind of compressor lubricant oil (tell this to AC guys when you want a regas).
    – Al_
    Commented Jul 31, 2018 at 19:55

1 Answer 1


Has it got the clutchless compressor or the clutch equipped one (have a look in the engine bay and tell me if there's a wire coming from the compressor's pulley or a wire coming from the compressor's back)?

If yours is the clutch equipped one first check if the front part of the pulley (the clutch hub) is rotating when AC is on. If not, bring out a multimeter, unplug the clutch coil terminal and check for resistance on the compressor side. It should show a reading between 3 and 6 Ohms (a new clutch coil in my possession shows 4.3 Ohms in this moment).

If not, the clutch coil is open. Very common with the Delphi CVC compressor, also happened on my Agila A with the 09167048 CVC clutch equipped compressor, it's a thermal fuse on the clutch coil which goes open. It's supposed to save the serpentine belt in case of compressor seizure, but can apparently go out earlier than it should, since my 15 year old compressor is still doing its job wonderfully after receiving a new clutch coil. I personally don't recommend bridging that thermal fuse, since it's there for a reason, but the aftermarket coil in my possession doesn't feature one.

720 kPa sounds like your compressor is pumping nothing, provided ambient temperature is around 28°C. 720 kPa is in fact the approximate static pressure of R-134A refrigerant at 28°C. If you want to test refrigerant static pressure vs ambient temperature by yourself, look for an R-134A Pressure vs Temperature chart on the net. Remember that the pressure transducer is located on the high side and that there's no low pressure sensor or switch at all when the compressor is of the variable displacement type.

Static pressure won't tell you nothing about charge weight though, unless the charge weight got very low (and i'm talking about charge weight because systems featuring CVC compressors have to be charged in terms of weight, since the compressors have a valve that adjusts the high and low pressures to optimal values, so never think about charging it up by yourself with canned refrigerant).

If instead you have the clutchless compressor, well, it's a different kettle of fish.

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