Fan noise when car is off draining battery over night
#1
04-14-2010, 10:40 PM
Fan noise when car is off draining battery over night
Folks,
I have a 1999 A4/2.8 Quattro...yesterday, I noticed a weird "fan" type of noise coming from the right side, near the radiator, just below the air duct (none of the 2 big radiator fans). After I shut down the engine...after 4-5 minutes, the noise dissappeared, but after another 4-5 mins it came back on...I'm not sure where or what exactly generates that, but I hear it and I can feel a draft right next to radiator. What's weird is that it goes on & off every 5 mins, even with my engine off...last night it drained my battery and I had to recharge...the only way to stop this on/of noise is to disconnect the battery...
After I charged the battery, I ran ODB2 diagnostics and no fault code came up. When I ran VAGCOM, I got the following fault code:
Address 01: Engine
1 Fault Found:
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
Readiness: 0000 0101
After a reset, no further codes appeared, yet the fan keeps going on/off every 5 mins...any clues what it could be?
Thx
I have a 1999 A4/2.8 Quattro...yesterday, I noticed a weird "fan" type of noise coming from the right side, near the radiator, just below the air duct (none of the 2 big radiator fans). After I shut down the engine...after 4-5 minutes, the noise dissappeared, but after another 4-5 mins it came back on...I'm not sure where or what exactly generates that, but I hear it and I can feel a draft right next to radiator. What's weird is that it goes on & off every 5 mins, even with my engine off...last night it drained my battery and I had to recharge...the only way to stop this on/of noise is to disconnect the battery...
After I charged the battery, I ran ODB2 diagnostics and no fault code came up. When I ran VAGCOM, I got the following fault code:
Address 01: Engine
1 Fault Found:
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
Readiness: 0000 0101
After a reset, no further codes appeared, yet the fan keeps going on/off every 5 mins...any clues what it could be?
Thx
Last edited by rockblock; 04-14-2010 at 10:58 PM.
#3
04-14-2010, 11:38 PM
That code is because the battery was low. Other than that Im not much help, and if theres a draft of moving air coming from your radiator it really cant be anything except for the electric radiator fan I would think... Other things that could make mechanical noises are your throttle body which is more of a quiet high pitch whine, or your HVAC fan but that is near the left passenger side beneath the windshield. Thats all I can come up with...
#4
04-15-2010, 04:36 AM
I had this same thing happen to me so you're in luck for help.
What you are hearing is the secondary air pump. Its function is cold start emission control. The fact that its not throwing a code means its doing its job when you start the engine. The problem with it coming on and off like it is is most likely a sticking relay. The fix has two options, the first of which is free. The relay is located in the ecu box on the driver's side behind the second firewall; big, black, plastic box, can't miss it. Open that up and you'll see the ecu and a small, gray cube that is the relay. Unplug the relay, give it a shake and plug it back in and put everything back together. If you do it with the battery disconnected, plug the battery back in and go drive for 50-70 miles to get all the readiness codes enabled again and see if that has fixed the problem. If the problem persists, proceed to your local stealership and buy a new relay, which SHOULD take care of it. Unfortunately, the relay can be pricey so try the shake method first. Good luck!
What you are hearing is the secondary air pump. Its function is cold start emission control. The fact that its not throwing a code means its doing its job when you start the engine. The problem with it coming on and off like it is is most likely a sticking relay. The fix has two options, the first of which is free. The relay is located in the ecu box on the driver's side behind the second firewall; big, black, plastic box, can't miss it. Open that up and you'll see the ecu and a small, gray cube that is the relay. Unplug the relay, give it a shake and plug it back in and put everything back together. If you do it with the battery disconnected, plug the battery back in and go drive for 50-70 miles to get all the readiness codes enabled again and see if that has fixed the problem. If the problem persists, proceed to your local stealership and buy a new relay, which SHOULD take care of it. Unfortunately, the relay can be pricey so try the shake method first. Good luck!
#5
04-15-2010, 09:30 AM
I had this same thing happen to me so you're in luck for help.
What you are hearing is the secondary air pump. Its function is cold start emission control. The fact that its not throwing a code means its doing its job when you start the engine. The problem with it coming on and off like it is is most likely a sticking relay. The fix has two options, the first of which is free. The relay is located in the ecu box on the driver's side behind the second firewall; big, black, plastic box, can't miss it. Open that up and you'll see the ecu and a small, gray cube that is the relay. Unplug the relay, give it a shake and plug it back in and put everything back together. If you do it with the battery disconnected, plug the battery back in and go drive for 50-70 miles to get all the readiness codes enabled again and see if that has fixed the problem. If the problem persists, proceed to your local stealership and buy a new relay, which SHOULD take care of it. Unfortunately, the relay can be pricey so try the shake method first. Good luck!
What you are hearing is the secondary air pump. Its function is cold start emission control. The fact that its not throwing a code means its doing its job when you start the engine. The problem with it coming on and off like it is is most likely a sticking relay. The fix has two options, the first of which is free. The relay is located in the ecu box on the driver's side behind the second firewall; big, black, plastic box, can't miss it. Open that up and you'll see the ecu and a small, gray cube that is the relay. Unplug the relay, give it a shake and plug it back in and put everything back together. If you do it with the battery disconnected, plug the battery back in and go drive for 50-70 miles to get all the readiness codes enabled again and see if that has fixed the problem. If the problem persists, proceed to your local stealership and buy a new relay, which SHOULD take care of it. Unfortunately, the relay can be pricey so try the shake method first. Good luck!
Last edited by rockblock; 04-15-2010 at 09:55 AM.
#7
04-15-2010, 02:46 PM
BINGO !!!...got it out and gave it a few taps & shakes and the issue seems to have gone...it's been 4 hours now and no noise (let's hope I didn't destroy it completely and will still kick in when needed)...thx A4Cragman, you're a life-saver!
#8
04-15-2010, 06:50 PM
Not a problem man, that's what this forum is for, helping each other out. I'm glad it worked for you, at least so far. You'll know if you made it worse if you throw a CEL within the next day or two.
