Issue with Proximity Sensor during calls - Continued v2

I returned my original iPhone 4 for the proximity sensor issue back in July and tried an Android phone for a few months. A couple of weeks ago, I bought a new iPhone 4 at an AT&T store and surprise, surprise, it had the same problem. I exchanged it at the Apple store and while the "genius" told me it was a known issue that wouldn't be fixed by an exchange, so far I have had no issues. I found it interesting that the Sr Advisor on the phone told me to take it in for exchange but the genius said the new phone would have the same issue. Sounds like Apple needs to get their story straight. Anyway, it seems to be working now so I'm happy. The serial number of the new (exchanged) phone starts with 5K0450. Not sure if this adds to the consensus opinion about phones beyond a certain build date, but just thought I would share.

Exactly my experience. AppleCare Tech Support said exchange the phone, even set up the appointment at the Apple Store for me, and the 'Genius' insisted exchanging wouldn't fix it.

Only problem is, the 'Genius' was wrong - it took some courteous but serious arm twisting, but exchanging did fix it. And not just the PS; the in-call audio quality is dramatically better than that of my first iPhone4, to boot. I'm completely happy with the piece of iPhone4 hardware I have now.

I understand how firmware/software could influence the PS behavior, but the primary defect must be hardware-related. I believe the phones are manufactured in more than one factory (don't know that for sure) and that it's not necessarily 'older' phones only which have the problem; my 'good' replacement phone had an earlier manufacture date than my original 'bad' phone. Where it was built may matter more than when it was built, though I would sure hope that QC had improved in more recently built devices regardless of their source.

The "primary defect" could be hardware related. Trouble is, unless some serious hardware website does some real testing - or takes some apart and find out if they have changed the actual sensor - it is almost impossible to tell with confidence.

A bigger question - and testable - is whether software can compensate. We've seen enough to know it can, at least, make it better with a good number of people reporting that, using the same hardware, the latest update solved their problems. And a few people who said it didn't. Wish we had more reports, good or bad, since that would help narrow things down.

Wouldn't be surprised to learn that the PS itself is a component manufactured by more than one supplier, further complicating sorting it all out.

I believe you are correct that Apple has made some software-based compensations which seem to have helped some 'victims'. I also suspect that the number of phones potentially affected is large enough that Apple doesn't have any interest in publicly acknowledging they have a problem - it could prove to be very expensive to 'do the right thing' in that scenario. But I will give them props for having replaced many phones.

I don't recall any website being able to say where the sensor was from, but I've hear people suspect it was Texas Instruments. But you're right, it could be multiple sources, complicating the matter. Just another mystery.

I've seen very few people saying they have the problem since 4.2.1 - maybe 5. I would normally consider that low of a number to be pretty meaningless, but it may also just reflect a lot of those who complained before simply aren't posting anymore.

Since some of the rumors are that post week 42 units "work" - at least the 3rd time I've seen that claim starting back around week 26 so more feedback needed on that too - maybe between the two possible changes most of the problem is gone. I hope so.

I returned my early Iphone4 because of proximity sensor problems. Like others, I got tired and frustrated after apologizing to everyone I put on mute or beeped numbers in their ear during a call. I wanted to make sure I was within the 30 day window, so I returned the Iphone and returned to using my old phone. We'll I missed the phone a lot and checked this forum daily hoping for good news. Since a number of users were having better luck with newer phones or 4.1/4.2 software, I decided to take the plunge again. I went to the AT&T store and got another one loaded with 4.1 software on 11/27. I wanted to wait before posting this to make sure it was working properly, and I'm happy to report that even after upgrading the phone to 4.2, I have have had zero problems with the proximity sensor.

That's pretty much what I did. First phone (well, three of them) had too many problems so I waited for 4.1. Much better, even if it is still too easy to reduce the distance the screen will come on at.

Eventually I want to do some testing using the Call Guard app so I can try to use the phone without being careful and then check the app to see if it ever shows any cheek taps. I know if I put it on my shoulder, I can have a problem, but I can live with that for the other improvements over my 3G.

Hi ,

I'm an iphone 4 user from India. I had been follwing this thread closely to determine whether to put my hard earned money intto this device or not, as this problem can make the phone useless.

I recently bought an iphone 4, and in the first week had zero proximity sensor issues. I updated to 4.2 and now, sometimes ( but very rarely) the proximity sensor acts up and doesnt swtch off the screen. Also I noticed that it does it when i carry out another task while on a call and then hit the touch to return to call button quickly and out the phone to my cheek: guess it doesnt have enough time to react?

Well, this is new.

I've done a lot of different tests, but never one that involved doing something else on the phone while on a call.

But perhaps there is something you could try if you don't mind doing the tests.

One of the things I did find on my tests is that, when the phone starts during on when too close (or on) the ear, I can reset the distance by holding it further away - say 6 inches or more - but for several seconds.

It is possible that what you are doing is a new way of creating the problem, but it is also possible that you can reset the distance.

I suggest the following test:

1. When you go back to the phone display, wait a couple extra seconds.

If that solves the problem, at least we know once the problem occurs, the "solution" is the same.

2. If that doesn't work, try putting it up to your ear as before, but then pull it away again - 6 inches or more for several seconds. See if that resets it.

If not, I have no idea.

But if either of these works, your experience may be something to pursue further.

Please let us know what happens.

that phone is simply broke...

take it back and get a new one bro... and if you get another broken one take that back until u get one that works...

there... that's the best fix anyone can give you.

Add me to the list of those who have experienced the issue. mid-call, suddenly the other party can't hear me. I take my phone away from my cheek to find the mute button activated. unmute and put back to my cheek - sometimes works, sometimes not...

Happened pretty regularly.

After updating to 4.2.1, I haven't experienced the problem...

Hi there everyone!
I want to report that my iPhone 4 is working perfectly after 4.2.1.
The PS sensor works like the 3GS one, switching the screen at 2" consistently.
I try to fool it and redo all tests, but the erratic behavior is gone.

I quickly read the topic, and have seen a few people reporting that the problem still
exists after update. That's true? It's seems very strange to me. Different hardware, maybe?

Welcome back!

Interesting report. We've had people say 4.2.1 solved their problem, but I don't recall anyone actually reporting in detail how their phone acted until your report. Very useful.

As I mentioned recently, one test (#6) seems to be solved, but I can till "fail" #3, getting the distance down to 1/4 inch. But I did have the feeling that it took more effort to reach that point.

I went to two Apple stores today. Again, every phone that had 4.2.1 passed test #6. At the second store, they had three from week 46 (unfortunately, only one had a sim to get a signal). Interestingly, it still had 4.1 on it so, based on ALL the other phones I've checked with that version, I expected it to fail that test. But it didn't. Screen never came on once it went off. Never saw that except with 4.2.1 before.

Now, we've had people report that maybe the phones were better starting with that week. But we had the same claims back with week 26 or 27 and something like 35. In all cases the reports were too few to base much on them and they weren't taking the tests to get some hard, repeatable, info on.

So I wanted to try test #3 on the one I found. I didn't have anything to actually measure the distance, but basically, besides passing test 6, it also passed test 3!!! It did lose a little distance, but not much. Definitely stayed off much further away than I ever got before. I'd guess at least an inch - maybe more.

Remember, that phone still had 4.1 so it may be that there is a difference in the hardware. OTOH, it is just one phone. Could be a fluke. Hopefully I'll get more time to do further checking, though I suspect by then all the phones will have been upgraded.

Still, it will be good to see if I can find enough later phones to create a pattern of success. If the Apple stores start getting more newer units on display, that will help.

I shoot a very small video of the PS working in iOS 4.2.1.
Compared with my previous video with the same iPhone 4, I can tell that Apple
are still reducing the power on the IR LED, but the minimum power has been INCREASED A LOT!
With the previous firmware you can make the IR light almost disappear with the card very close
to the PS. Now in the same situation, the IR light is dimmed, but clearly visible.

Also the pulses are faster now. It's almost impossible to see the IR light blinking as before.