Can You Help? Saab 9-5 Air Conditioning Problem

I got this question in from a friend in Sydney today. Any of you 9-5 owners had the same problem? Any of you know of a fix?

Fire away in comments…..


Hi there,

I have a 2006 SAAB 9-5 Sports Wagon which apart from one issue is an awesome car.

The one issue seems to be related to the usage of the air-conditioner, which reduces the cars power down to a fraction of its normal power.

This doesn’t happen as soon as the AC is turned on. Perhaps 10 minutes later… it can vary. I most notice the effects in start stop city routes.

If I could describe the behaviour from a driving perspective:

– it’s most pronounced when moving off from a complete stop.
– pushing down on the accelerator has a distinct lag.
– then after the power kicks in, it has a very sluggish feel. Perhaps only 30% of normal power.
– turning off the engine or the AC will typically get rid of the issue…. but not instantly. After a few minutes.

I’ve taken it to a couple of mechanics and they seem unsure what could cause that behaviour. Because it doesn’t kick in straight away, they don’t get to see it in action.

Any ideas or thoughts would be most appreciated.

As I said, it’s a great car and I’d love to have my AC back in use this summer.



As I said, if you know of a solution (that doesn’t involve selling the car 🙂 ) then please feel free to enlighten Piers in comments.

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  1. First of all, my condolences. I know that such intermittent faults are frustrating.

    I think the reason this is so frustrating is that you have more than one fault causing this issue, and when both act up together you experience symptoms.

    1. Your A/C compressor clutch is obviously NOT disengaging your A/C compressor when you put your foot in the throttle. The faults here could be in any part of the system, but the most frequent problem would be just the switches or wiring. At worst, the clutch mechanism itself is bad, which would put you into a new compressor/clutch for the car. Not cheap.

    2. It sounds as if you could have a compressor that’s on its last legs and struggling to run OR your expansion valve is stuck open. Either would cause the compressor to be a much higher than typical load on the engine. I cannot recall if the 9-5 has a high-pressure switch or not, but if it does, that would be a potential point of failure, too. (The high-pressure switch should disengage the compressor when the expansion valve allows too much pressure in the system.)

    Recommended course of action:
    1. Observe very carefully how the system responds the next time it happens. In a low gear, try wide open throttle. If the A/C is still blowing cold and the car is still bogged down, then the A/C compressor clutch isn’t disengaging as it should.
    2. Observe carefully how cold the A/C is when the problem has been going on for a few minutes. If it is getting warmer, have your mechanic check the expansion valve and high-pressure switch.

    I hope this helps.

    1. As it comes and goes slowly, I suspect a temperature-related issue, especially when it is more pronounced in slow traffic (poor convection cooling). Do both radiator fans really work, on both high (both fans have full voltage) and low speed (fans connected in series)? There are three relays controlling this. The accelerator lag may very well be high intake air temperature due to a hot intercooler (can be seen with an OBDII-adapter and Torque for an Android phone).

  2. From what you describe, it sounds to me like the AC compressor is on its way out. Next stop on the failure parade will be the clutch coil overheating and failing (pops a thermal fuse inside–what a smell!). Eventually the compressor will just seize up.

    How many clicks on this car? My experience with 9-5 AC is that the compressor on mine ultimately failed around 400k km, several years back. I bought a used compressor from a recycler with maybe 150-200k on it, installed and vacuumed/re-charged it at home. It was working just fine when I finally sold the car a couple years back with about 500k km on it.

  3. A/C system charge amount is critical on these cars as they use a variable displacement compressor. Step # 1 would be to evacuate and recharge with the correct amount of r134a. And if the cooling fans are not up to speed high side pressure will go really high, making for lots of load on the already hot heat soaked engine. You can remove the outside temp sensor from it’s bracket in the grille and move it over behind the intercooler if you want to see how hot it gets. Very possible the compressor is on its way out.

  4. I would ask the mechanic to interrogate the Trionic for fault codes first.

    An a/c which leaves the car with “only 30% of normal power”? I suspect this is the result of some kind of electronic limitation within the Trionic itself.

  5. The AC compressor failing theory seems off to me. He said it feels like 70% of the power is gone. If the AC compressor was able to put that amount of drag on the belt the belt would simply be destroyed in short order. No way that belt can dissipate 100+ HP. My guess is it is an electrical short or bad ground. Maybe when the extra fan kicks in for the AC it is sending power down another circuit that has crossed wires. Not sure what path that would be.

  6. I have similar issues on my ’02 Estate.
    There could be a whole range of things going on here. Ask me how I know…lag is most likely related to boost, being fundamentally a turbo related issue. Mine has done 200K and does not like the hot weather at all and I have weird boost issues in the heat. Fuel supply issues should be a suspect, and the pump fails in the heat too, starving the engine, with T7 dropping boost off to compensate. I am grappling with all of these too, and the big one is when the ambient temperature gets over 30 degC you lose a lot of available boost, also part of the protection built into T7. Over 40 you get nearly no boost at all. Petrol grade in hot weather on these engines should be 98RON too.
    If the compressor is failing and there are issues around that, then a Tech 2 interrogation probably won’t show anything much but give it a go to find out anyway. It is worth the cost.
    Run the aircon diagnostic too, pressing auto and off simultaneously with the ignition on, and do this several times, engine running too. If it throws a code on the RHS of the display then that will point you in the right direction. But I’m betting It won’t show anything. If the temperature gauge on the dash drops suddenly too, then the aircon will be progressively disengaged, again to protect things. Clever but annoying.
    Try resetting the ECU too, dropping the battery out for a decent charge, while you are at it. The 9-5 really likes lots of volts to run everything well.Which brings the next issue up, a slowly failing alternator, something that just creeps up on you silently. In the heat, the alt progressively fails, so put a voltmeter across the terminals when the car is cold and also very hot, with the aircon on. If you have less than 13.8V then the load on on the battery and elec system is going to drag the engine heavily. Quick to check too.
    Last question to ask, how cold is the air coming out of the vents at 22degrees outside and when it is 33 outside. That might give the biggest clue.

  7. I have an ’07 9-5 Sportcombi and have been chasing a similar issue for the last 3 years, except I don’t believe mine is AC related. Same symptoms though…as soon as the car warms up, I lose quite a bit of power and fuel economy drops by 30% (for reference, prior to this starting, I was getting 30mpg (US) @ 75mph. Now i’m averaging ~20mpg for long drives).

    Now, the strange thing is that this began to occur after my Cadillac dealership removed the head to fix a timing cover leak. I can hear the grumbles begin…but this was several years back, the car was covered by GMPP, and i was under the impression that it was a Saab tech working it (it wasn’t.). They of course wouldn’t touch it and thought I was crazy, so i’ve had multiple techs take a look at it, check the timing, turbo boost, back pressure, fuel pump, and replacing several sensors, the ECU, etc. Basically once the car warms up, it is in a perpetual state of knocking (per the Tech 2) so it floods it with gasoline to remediate the situation.

    The one thing we haven’t done yet is pull the head – the prevailing thought now is that whenever they pulled the head, they sent it out to a shop to get it machined and they took too much off changing the compression ratio. Now that the head

    Anyways, didn’t mean to thread jack – but at least you know you’re not alone! Good luck!

    1. Tulsaab, have you had the valve timing rechecked? It’s common for techs less familiar with Saabs to get it off a tooth when doing head work which can result in a variety of symptoms. I’ve seen 3 cars in 2014 with exactly this kind of complaint/cause!

      1. Thanks for the advice, Rick – I have had two Saab techs remove the valve cover and check the cam timing. However, now that the head gasket is starting to leak quite a bit and the retorque didn’t help, I will have ample opportunity to check for any defects due to the lack of knowledge from the previous assembler. The shop i’m taking it to is Taliaferro Imports, which is famous stateside for it’s manufacture of high quality aftermarket parts and generations of Saab knowledge, so i’m optomistic that by the time I get my 9-5 back from them, not only will the situation be remedied but I might have a bit more pep to boot!