TICKING SOUND IN REAR CABIN

[iC805]

Hi All - lately I have been hearing a "ticking" sound coming from what seems to be the rear cabin/trunk area. The sound is very low and sounds like someone tapping there fingernail on a desk slowly then faster and faster with shorter lengths until it suddenly stops. The sound last's about 7 seconds. It usually occurs when I first start the car regardless if it's been sitting overnight or a couple hours, sometimes I start to drive and the sound goes away. It may be happening the whole time I've owned the car but the past couple months it really stands out. No difference in the feel of driving at all.

It almost sounds like something is self checking or balancing out. Could this be the Stabilitrak or something similar? I tried recording the sound on my iPhone 6 but it can't seem to capture the sound so I'm waiting for a friend to come this weekend with a sound sensitive filming mic. Trying to avoid taking the car to a shop for them to find "nothing" and charging me. No service lights or warning have come up.

2010 L99 2SS @ 98,000 miles.

Cheers from SoCal

[The_Stache]

This is the self diagnostic on the fuel pump, occurs just after the engine comes up to temperature. Doesn't happen on every startup though, but it is regular (every 3-7 startups).

[iC805]

Originally Posted by The_Stache

This is the self diagnostic on the fuel pump, occurs just after the engine comes up to temperature. Doesn't happen on every startup though, but it is regular (every 3-7 startups).

Man THANK YOU for that really comforting knowing what it is. Cheers.

[Skyblu]

also know as the "trunk monkey" lol.

[Spec]

Originally Posted by The_Stache

This is the self diagnostic on the fuel pump, occurs just after the engine comes up to temperature. Doesn't happen on every startup though, but it is regular (every 3-7 startups).

Always wondered what that was. I hear it after every start up. 3 ticks... I did know it had to do with the fuel system, but never really thought enough of it to research exactly what that was. Thanks.

I like to warm my car up before getting her going... I actually wait until I hear that 'ticks' before I get up and go. I know its a mixed bag with people offering opinions on whether you should warm your car up in the morning or not... but I reckon it doesn't hurt... and I actually feel the car run smoother when I do.

[kmarshall2121]

when it starts - dont drop below 55MPH! could be the makings of a new Keanu Reeves movie (Speed 3??)....

[Stormcloak]

Originally Posted by The_Stache

This is the self diagnostic on the fuel pump, occurs just after the engine comes up to temperature. Doesn't happen on every startup though, but it is regular (every 3-7 startups).

Thanks for this info!!

[camarosspower]

I always thought it was the evap solenoid. When it went bad I wouldn't hear it again until I fixed it. Now I hear it every time

[JetPilot45]

I have never noticed. I will pay attention next time. I have a loud exhaust and my music is always tuned up so that is probably why.

[Russell James]

Originally Posted by camarosspower

I always thought it was the evap solenoid. When it went bad I wouldn't hear it again until I fixed it. Now I hear it every time

That's what it is.

PCM clicks it, seals the tank, then applies engine vacuum, click it to seal off that vacuum, and a few seconds later checks the pressure sensor to see if it is maintaining a vacuum. Then clicks and releases the vacuum.

Leave your gas cap loose, and if it fails two of those tests in a row, it'll turn on your check engine light.

[JaysSS]

I have been figuring out the best way to google search this for week and finally I have found it! Thanks for the information!