A/C diagnostic procedure?

[jbarber]

Other than the service manual, (which I need to buy) is there a place that lists how to retrieve the climate control diagnostics, and what the codes mean?

The compressor clutch won't engage, so my first guess is just that the pressure is too low. I'm not the least bit qualified to work on A/C, so will take it to the dealer, but it would be nice to know what the car thinks about it, anyway..

Thanks,
--jim

[jbarber]

Never mind, I dig some digging and found the procedure to retrieve the A/C codes.

Now the question is: What's code "13" mean?

Thanks,
--jim

[Beav]

13 = Sun Load sensor

Lee was having a #13 problem recently, you might PM him for the diagnosis info and what he found.

[jbarber]

.. for the quick replies. The interest the people in this group have in their cars and swapping info is just outstanding! I'll ping Lee, and see what he found out.

The sun load sensor looks like a garden variety cadmium-sulphide unit.. If it is, I may just see how much trouble it would be to dig it out of the dash. If memory serves, they show >100,000 ohms dark, and <1000 ohms in sunlight. Should be easy to test it and the connector if I can get to it.

--jim

[lee]

This may be a stupid thing on my part (or maybe Subaru's), but to test the diagnostics you have to be out in daylight (or maybe a bright shop).

In my dim garage I kept getting code 13, and I tested the sensor itself and took the dash half apart to test voltages at the climate control module. Everything was fine but I still got code 13.

Tried it once by chance out in my driveway, no codes. Tried it again in my garage, code 13 again. Backed it out and tried again in sunlight, no codes. A light began to come on....

I remember an old engineering text in which the author (Hayt) was trying to be funny by saying, "Holding this text closer to a source of illumination will not shed any more light on the subject."

My twist to his words would be, "working in the dark will probably leave you in the dark."

[jbarber]

Thanks!

It was dark out when I ran the A/C diagnostic, so the code may have been bogus. I'll trot out there and try it again in the daylight.

--jim

[jbarber]

Well, the A/C diags show "00" when you shine a flashlight into the sensor, but the compressor still won't engage.

Could still be pressure, I s'pose. Looks like it's wheel bearings and A/C check at the dealer this week.

Thanks again for the tip, Lee. It saved me from making a fool of myself, at least in that regard. :-)

--jim

[lee]

got a volt/ohm meter?

slide the drivers seat back and look up under the dash to see the connectors for the ECM. You should see 4 yellow connectors. B59 has 22 wires, B60 has 12, B61 has 16, and B62 has 26.

With engine on or off, and with one lead of the VOM at ground, and a thin probe (to reach up to touch the wire inside the connector) you should see 10-13 volts on pin 9 of connector B61 (a brown wire on a corner of the connector) when the A/C is on (this is the signal wire from the climate control unit to the ECM). There should be zero volts when the A/C is off.

If you have this then the climate unit is probably working fine.

Next step, see if the white/black wire on pin 8, connector B60 is at zero volts when the A/C is on, at battery level when A/C is off (engine has to be running for this test). This is the ECM telling the compressor to go on or off.

If this is OK, then it may be a pressure problem. To test this (engine off) lift up on the cannister to the left of the radiator (looking from the front) and you should be able to see the trinary switch on the metal line just before it goes into the condensor. Note where the lite green and blue/red wires are. Pull off the connector and see if there is zero resistance between the pins for the wires I just mentioned (not in the connector, on the switch), If there is zero resistence, then the low/hi pressure switch says you are within limits and the compressor failing to come on is not due to insufficient freon.

There are other tests if you make it this far. Let me know if any of this doesn't make sense (I've never been a good writer). If all this passes, let me know, there are more things to check and eliminate, like A/C relay itself, throttle position sensor, water temp sensor, etc.

BTW, Beav posted the A/C wiring schematics some time ago in his personal locker. If they're not still there, let me know, I'll scan them in and e-mail or whatever. Assumes of course you're comfortable with tracing electrical gremlins.

[jbarber]

Lee,

That's great info, thanks!

I do have a VOM, and have printed off your message for reference.

Since the car will be at the dealer's shop this week for wheel bearings anyway, I'll have them check the charge. If it's ok, I may tear into it myself, at least to identify what's what. If I get that far, I'll certainly hit you up for the schematics, thanks!

--jim

[Chad]

I took my car to the dealer to get the AC diagnosed. The compressor wouldn't engage. This is what I found:

r-12 IS EXPENSIVE

shop installed dye to check for leaks, no leaks visible, but the freon wouldn't stay in??? Hmmmm. 2 lbs gone. They tell me it'll be 3 hrs diag to tell me that it's coming from the evaporator core under the dash. The dealer says "they never leak" so for $75 bucks I get a used one. Install it myself (freon had leaked out anyway) Took it back to have it filled. compressor seal blew out. Got a new compressor. Installed it myself. (The shop pulled out what they put in) Then took it back, they filled it, and I still have A/C.

That was an expensive week with no A/C.

Not trying to burst your bubble, just giving you a heads up....

[jbarber]

Chad,

Oh I know, it won't be cheap. Living in Ritzville, though, you experience the same weather as I do outside Selah. It will get REALLY hot in the next couple of months, and I'm far too attached to A/C to go without it.

With just an ounce of luck, it won't be an evaporator or condensor leak, and I'll be able to squeak by for a few hundred dollars. Can't remember the last time I had an ounce of luck, tho.. :-(

--jim