KyleH

iTrader: (1)

Background:

Back in December the air conditioner was working fine, as it had been since I purchased the car in October.

I pulled the original engine and swapped in a GTE vvti engine. This engine had all the original accessories on it, including the AC compressor..

Took the car to the local shop to have the AC charged up. They stated the compressor was bad as it was not able to hold any pressure due to a pressure release valve or something that was faulty.

No big deal, so I swapped my original AC compressor onto the new motor.

Took the car back to the shop and they found that a couple of o-rings were shot and they replaced those. They said at that point the system would hold pressure, but they couldn't get the A/C to work.

I picked up the car and noticed the outside temp gauge reading -22. So I got out and checked/tightened the plugs on the sensor. After restarting the car the gauge began reading normal temp. However, when I turn the AC on, the car idles up but the compressor doesn't turn on. After about 3-5 seconds the AC light begins flashing and the car's idle drops back down to normal.

I read about pulling the codes and so I did that and got the following codes:
21 - solar circuit pass side
24 - solar circuit driver side
46 - air mix servo motor driver side

None of these codes make me think they have anything to do with whether or not the AC should work or not. In fact, since I pulled the codes in my garage at night, I'm not worried about 21 or 24, and I know the driver's side heat/air control isn't working correctly, so not surprised there either.

Looking for any help to get my AC working before the heat comes!

Thanks!

KyleH

iTrader: (1)

Easter bump. Still looking for any insight on this one. Alternatively, if anyone has a factory service manual link, specifically for the AC system, I'd greatly appreciate it. I've at least checked the A/C relay, and it seems to be working fine, so that's not the issue. Still hunting...

Mcon

iTrader: (1)

You probability have a leak on your system and that is way your A/C compressor no work at all. Also, can be the clutch on the A/C compressor that is bad as well? The first think that you need to do is,try to use any A/C gauges to check the pressure on your A/C system and the gauges tell you if the A/C system have Freon on it. If not, that let you know that you have a leak. And if the gauges tell you that the Freon is good on your A/C system, is maybe your clutch or maybe you have power in your relay but not on your compressor? Just do that fist. Use gauges to see that the gauges say. Good luck

About the air mix servo; No mare what is not working correctly, your a/c system have to work, no 100% correctly, but work.

PS.
TROUBLE SHOOTING

SELF-DIAGNOSTICS
An Electronic Control Unit (ECU) within A/C-heater control
panel monitors system circuits and stores trouble codes in memory if
problems are detected. All codes, except Codes 22 and 23, are stored
in memory. Malfunction is current if Code 22 or 23 is displayed. To
retrieve stored codes, see RETRIEVING CODES. Codes are displayed at
temperature display.
RETRIEVING CODES
1) Simultaneously press and hold AUTO and recirculated air
switches. Turn ignition on. All indicators will flash 4
times, at one-second intervals. Tone will sound when indicators flash.
2) A/C system will enter self-diagnostic mode. To end
indicator check, press and release OFF switch. Read codes at
temperature display.
3) If trouble code is displayed, proceed to appropriate
trouble shooting procedure. See DIAGNOSTIC CODE IDENTIFICATION table.
Codes are displayed in ascending order. To slow rate at which codes
are displayed, press fresh air button to change display to step
operation. Each time fresh air button is pressed, display changes by
one step.
4) If tone sounds as code is displayed, problem currently
exists. If tone does not sound as code is displayed, problem occurred
in past and does not presently exist.
Code Diagnosis
00 ................................................ Normal
11 (1) ............. In-Vehicle Temperature Sensor Circuit
12 (2) ................ Ambient Temperature Sensor Circuit
13 ................. Evaporator Temperature Sensor Circuit
14 .................... Coolant Temperature Sensor Circuit
21 (3) .............................. Solar Sensor Circuit
22 (4) .................... Compressor Lock Sensor Circuit
23 (4) ........................... Pressure Switch Circuit
31 .................. Air Mix Door Position Sensor Circuit
32 ................ Air Inlet Door Position Sensor Circuit
33 ............... Air Outlet Door Position Sensor Circuit
41 ....................... Air Mix Door Servomotor Circuit
42 ..................... Air Inlet Door Servomotor Circuit
43 .................... Air Outlet Door Servomotor Circuit
(1) - If in-vehicle temperature is -4 F (-20 C) or less,
Code 11 may set even though system is normal.
(2) - If outside air temperature is -58 F (-50 C) or less,
Code 12 may occur set though system is normal.
(3) - If testing is done in a dark area, Code 21 may set
even though system is normal. Shine a light at solar
sensor and recheck codes.
(4) - Malfunction is current. Code is not stored in memory.

ACTUATOR CHECK
1) Perform step 1) of RETRIEVING CODES. When system enters
self-diagnostic mode, press recirculated air button. Each mode door,
motor, and relay will operate at one-second intervals. Press fresh air
button to display codes one at a time, and perform step-by-step
actuator check.
2) Check airflow and temperature by hand. Tone will sound
each time display code changes. Each display code is associated with a
system operating condition. Press OFF button to
cancel actuator check mode.

Good Luck

KyleH

iTrader: (1)

Thanks for the input. I'd run those diagnostics, only finding codes that didn't pertain to whether the AC would work or not. My next step was to try and manually activate the clutch on the compressor in hopes I could get it to fire up (or not) and determine whether the compressor had quit working.

I couldn't for the life of me find a service manual online for the GS, but I did for the IS, which likely shares the same compressor. Based on the trouble shooting guide, there is a single pin on the 3 prong connector on the AC compressor that engages the clutch to activate the compressor.

I found that when I jumped a 12 volt source to this plug, the clutch worked (I could hear a click). So I started the car and then jumped the 12 volts again and the compressor engaged. I let it spin for maybe 10 seconds. Then I plugged the connector back in and got in the car and started it. To my surprise, the AC started working! Since it was a cool day I couldn't determine temperature.

However, over the past couple of days temps have been 70 and sunny, so with the windows up sitting outside, the car gets warm enough to need AC. It seems to be cooling very well. But twice in the past 2 days the AC light has started flashing on me. But by cycling the AC off and back on, it kicks back on and stays on. At this point, I'm cautiously optimistic. I'm not sure why it suddenly started working as a result of me manually activating the compressor. I'm also a bit concerned about why it has since then given me the same blinky light (no AC) a couple of times. I'll report back with any updates.

wbmx1981

There is also an AC relay switch that engages or disengages the clutch you might want to check that out.

iToaster

The flashing AC light indicates an error in the compressor circuit. There is a relay responsible for controlling the magnetic clutch that you might want to check out, as it will cause the light to flash if it fails. It's in the relay box next to the diagnostic connector in the engine bay.

KyleH

iTrader: (1)

Great points! Before going to the length of jumping the compressor, I did test that the relay was switching. I had someone feel it while I turned the AC on and off and it was clicking. I also traded it with another relay in the box and found no change. I'm not suspicious that there may not be quite enough freon in there which could be why it's turned off on me a couple of times, as the shop didn't have the compressor running while filling the system. What's odd though, is if pressure is low I should be seeing that code I would think...

iToaster

Indeed, a pressure issue should throw code 23, but the compressor should also be running when filled. The repair manual only cites the compressor circuit as causing a flashing AC indicator. It's conceivable that there is a bad connection somewhere, possibly a wire broken inside the insulation making intermittent contact.

burteboy

The light is flashing because the amplifier is not receiving the rpm signal. It could be a bad compressor, broken wire,or you a/c relay. I would check the relay first. Then ohm out the rpm sensor wire at the amplifier. Another way check the wire from the connector at the compressor to the amplifier,your are checking continuity. If the wires are ok u need a compressor.

KyleH

iTrader: (1)

Just a quick update. No material change. The button sometimes still requires me to cycle it off and back on a couple of times a week. I have not been able to recognize a pattern or establish any sort of rhyme or reason why it does this.

Garz

When mine did that, it just simply needed to be recharged. Then good as new.

Mcon

iTrader: (1)

KyleH,

Lexus recommends that every three years, the AC system has to be recharged. Like I said before, check with the gauges to see what the gauge say. And please, let us know what are you found.

KyleH

iTrader: (1)

I'll report back when I get some gauges on the system and or any other changes that are worth noting come about. The AC system was completely refilled with the specific amount of refrigerant specified for a GS300.

burteboy

Let me know all the checks you have made. Flashing AC light normally happen when the relay is bad, bad amplifier, compressor which have the rpm sensor ,or an open circuit between the compressor and the amplifier. I think while you did your repairs athe rpm signal wire got damage. My computers r down I'm using my daughter iPad.

burteboy

The idle going up the ecu is getting a signal from the amplifier but it would drop when it cannot see the rpm signal. This is what I would advise you to check . Is the system fully charge ? If so hot wire the compressor and see if it would operate and cool the vehicle. If it don't come on you have a bad compressor. Another way is when you disconnect the power connector at the compressor check voltage have someone turn on the AC and check voltage. If no voltage. Problem is not the compressor which you can check by the hot wire method. You would have to check the fuse , relay and wiring. The amplifier should be good because it's seeing the switch turned on to have the ecu idle up the engine.