AC light blinking
Racer
Joined: Oct 2015
Posts: 1,810
Likes: 170
From: Colorado
This relearn procedure is what fixed my idle speed problem. disconnect the battery. Remove the air inlet from the throttlebody. Push the throttle plate closed. Have someone else reconnect the battery while still pushing the throttle plate closed. Then have the other person put the key in the ignition and turn to the on position ( don't start) while you still held the throttle plate closed. Once the key is in the on position, reconnect the air inlet to the throttlebody (as soon as the key was turned on you can quit pushing the plate closed). Then start the car with everything turned off, radio, ac, lights. Let run for about 5 minutes at idle. Don't touch the accelerator. Shut the car off, you can restart and drive as normal.
FIRST: try cleaning the throttle body. If the throttle body is dirty this will probably make it idle even slower. This procedure just re calibrates for the computer where fully closed throttle is.
FIRST: try cleaning the throttle body. If the throttle body is dirty this will probably make it idle even slower. This procedure just re calibrates for the computer where fully closed throttle is.
Last edited by Coleroad; May 26, 2018 at 02:03 PM.
Driver
Joined: May 2010
Posts: 83
Likes: 5
From: AL
Hey Jenpm et al-
I just replaced my AC compressor and am having this exact same behavior.
To recap
-r134a levels are good
-a/c is fine in park, where idle is ~800-900
-a/c is fine at speed, whether in drive or idle, IF the rpm's stay above ~800
-at 600 (i.e., if I slow or stop in drive), though, the a/c light blinks, and compressor turns off, so warm air comes out
-if I get the rpm back up (by putting in park or neutral and raising the RPMs), I can immediately turn it off and then back on
This is confirmed through 3 hours of driving on highways and slow roads, 100% consistent.
So- anybody have any resolution to this thread?
No codes for the a/c self test.
Only codes on the main diag are two oxygen sensors (for the level of fuel/oxygen mixture I believe), and those have been on for a bit.
My neighbor and I are flummoxed.
I just replaced my AC compressor and am having this exact same behavior.
To recap
-r134a levels are good
-a/c is fine in park, where idle is ~800-900
-a/c is fine at speed, whether in drive or idle, IF the rpm's stay above ~800
-at 600 (i.e., if I slow or stop in drive), though, the a/c light blinks, and compressor turns off, so warm air comes out
-if I get the rpm back up (by putting in park or neutral and raising the RPMs), I can immediately turn it off and then back on
This is confirmed through 3 hours of driving on highways and slow roads, 100% consistent.
So- anybody have any resolution to this thread?
No codes for the a/c self test.
Only codes on the main diag are two oxygen sensors (for the level of fuel/oxygen mixture I believe), and those have been on for a bit.
My neighbor and I are flummoxed.
Thread Starter
Rookie
Joined: Apr 2018
Posts: 35
Likes: 1
From: Fl
Bad rpm sensor in compressor
You need a new ac compressor. Rpm sensor is bukit in. Had the dealership confirmed. Bought mine from ebay , ship from miami. Could not get exchange. Just ate the cost, autozone price went down and purchased it locally. You need a new ac compressor. No codes willl rripped
Lexus Test Driver
Joined: Dec 2014
Posts: 8,213
Likes: 950
From: Fl
He said the compressor was replaced.
Driver
Joined: May 2010
Posts: 83
Likes: 5
From: AL
Thanks for the replies guys!
But yes, Bgw is correct, this is post-installation of a new AC compressor...
I also tried the a/c relay (swapped with the horn relay) but that didn't change the behavior.
My neighbor and I are going to hunt for the 'standard' idle speed, plus with/without a/c, with/without being warmed up, etc.
But are you saying that you had to buy a second compressor, Jenpm? The first one you put in was giving this behavior, but then you got a second one, and that fixed the problem??
But yes, Bgw is correct, this is post-installation of a new AC compressor...
I also tried the a/c relay (swapped with the horn relay) but that didn't change the behavior.
My neighbor and I are going to hunt for the 'standard' idle speed, plus with/without a/c, with/without being warmed up, etc.
But are you saying that you had to buy a second compressor, Jenpm? The first one you put in was giving this behavior, but then you got a second one, and that fixed the problem??
Driver
Joined: May 2010
Posts: 83
Likes: 5
From: AL
And as a side note; I don't think my RPM is off; it's about 600 in drive, about 800-900 in park.
I'm going to try to confirm what the normal idle ranges should be in different scenarios; my neighbor is leaning towards adjusting the RPM up (but it's all ECM now, not sure that's a good idea or doable!).
But if the real problem is a bad sensor, I'd almost be more inclined to fight with the supplier.
I'm going to try to confirm what the normal idle ranges should be in different scenarios; my neighbor is leaning towards adjusting the RPM up (but it's all ECM now, not sure that's a good idea or doable!).
But if the real problem is a bad sensor, I'd almost be more inclined to fight with the supplier.
Thread Starter
Rookie
Joined: Apr 2018
Posts: 35
Likes: 1
From: Fl
Bad rpm sensor
I went through everything you did, check relays, check freon level. Intake sensor. If ac light blinks at idle, and no cold air, but comes on at higher rpm- driving. Then it is the rpm sensor. The dealership check the resistance. My ac compressor was brand new. It really suck to buy a new one, vacuum, and refill the freon. Thats why i bought it locally so i can exchange it if it goes bad. Good luck
Driver
Joined: May 2010
Posts: 83
Likes: 5
From: AL
One last question it looks like: when you said 'comes on at higher rpm-driving", mine doesn't come on automatically (i.e., stop blinking and switch to cold), but it does function normally if I turn it off when blinking, then turn it on when my ROMs are higher...
Just wanted to be sure that my interpretation was correct.
So, very sad, yeah! Bought mine from AutoZone .. dunno what the options are...
Thanks so much!!
Just wanted to be sure that my interpretation was correct.
So, very sad, yeah! Bought mine from AutoZone .. dunno what the options are...
Thanks so much!!
I went through everything you did, check relays, check freon level. Intake sensor. If ac light blinks at idle, and no cold air, but comes on at higher rpm- driving. Then it is the rpm sensor. The dealership check the resistance. My ac compressor was brand new. It really suck to buy a new one, vacuum, and refill the freon. Thats why i bought it locally so i can exchange it if it goes bad. Good luck
Thread Starter
Rookie
Joined: Apr 2018
Posts: 35
Likes: 1
From: Fl
Yes. Same thing happenee to me. Had to turn off and on, i. Noticed highway driviing- no problem. City driving, stop and go, ac light blinks at iidle. You can look through threads to check the resistance of rpm sensor located at the ac compressor. Make sure the wire is grounded there,
Pole Position
Joined: May 2016
Posts: 3,101
Likes: 655
From: AZ
If you are not sure what the next step would be, I would try to put in more R-134. My theory is that when the engine is running faster, the R134 pressure in your system is adequate (Since it is being compressed) when your engine is running slower, the pressure drops below the minimum pressure threshold and the ac cuts out.
When you charged the system, it was probably in park, which is why the ac works in park.
Possibly you can check the levels when you are in drive with your foot on the brake.
When you charged the system, it was probably in park, which is why the ac works in park.
Possibly you can check the levels when you are in drive with your foot on the brake.
Driver
Joined: Aug 2018
Posts: 129
Likes: 31
From: OK
In fact, the opposite is true. If the system is low on refrigerant , the higher rpm will drop the suction side pressure and the low pressure switch will cut out the compressor. Once the rpms decrease, the low pressure side rises and would bring the compressor back on.
Lexus Test Driver
Joined: Dec 2014
Posts: 8,213
Likes: 950
From: Fl
If you are not sure what the next step would be, I would try to put in more R-134. My theory is that when the engine is running faster, the R134 pressure in your system is adequate (Since it is being compressed) when your engine is running slower, the pressure drops below the minimum pressure threshold and the ac cuts out.
When you charged the system, it was probably in park, which is why the ac works in park.
Possibly you can check the levels when you are in drive with your foot on the brake.
When you charged the system, it was probably in park, which is why the ac works in park.
Possibly you can check the levels when you are in drive with your foot on the brake.
Last edited by Bgw70; Jul 22, 2019 at 06:05 PM.