Hello,

On my '95, the PKE fob will lock the car by walking away from but, it doesn't unlock it, even manually pushing the door button. Also the hatch button doesn't work. I pulled the battery & it puts out 3.23 volts so that doesn't appear to be the problem. I did the reset as per manual instructions & it didn't make any difference.
Does this sound like a transmitter or receiver problem? Thank you!

Rex

 

Just guessing, but sounds like a receiver.

 

Additional information. The door button on the fob will not lock it, either. Only walking away locks it with just the hint of a beep. Which brought up another interesting 'feature'. The horn buttons don't sound the horn. Checked all fuses, all good. The power locks work fine with the door switches. Is there a horn relay somewhere? Thanks, again.

 

The fob buttons will not lock the door. It does not work that way.
That's why it's called PKE (Passive Keyless Entry).

If it locks the doors when you walk away from the car, and you get the "beep" sound from your horn that means the system is turned on and the alarm is armed.

Not sure why it's not unlocking as you walk back up to the car.
How old is the fob battery? These fobs seem to be really picky about having a good battery.
I'd try a new battery, since that's the easiest to try at this point.

 

You can turn off the unlock function by holding the manual lock button in the lock position for more then 3 seconds( I think 3 secs), hold the button in the unlock position till you hear the locking system cycle.
That should start it working again, if I had my FSM here, I would tell you the exact time it takes to cycle.

By the way, your receiver is fine.

 

I don't know age of the battery & I did a voltage test but, without a draw. I'll pop a new one in tonight & see what happens. Guess if that doesn't work I'll track down a wiring schematic for the car.
Do you happen to know where the horn relay is? I'll test the horns themselves in a bit, just to make sure they function. Thanks for your help.

 

It sounds like your key FOB is not transmitting. There is a ball bearing inside that rolls around which makes a contact to energize the FOB and tell it to start transmiting. If you gently shake your FOB near your ear, you should be able to hear the ball bearing rolling around. Your ball bearing is probably stuck or the contacts are dirty. The reason for this activating ball bearing is so that the FOB will stop transmitting when you set your keys down on your desk. If your FOB was constantly transmitting an RF signal, this would make short order of your battery. This ball bearing can be thought of as an ON/OFF switch that is activated and de-activated by simple motion of the FOB.

The energizing ball bearing is located under this cover, you can see it if you turn the FOB and look through small opening:


EDIT:
Found this additional information info from member "theadmiral94" :
"The FOB has a small ball-bearing inside a metal (gold) housing on the circuit board which can get dirty and get stuck. The housing can be gently snapped-off and the ball bearing and area gently cleaned and get the FOB working again (worked for ours). The ball-bearing 'wakes-up' the FOB transmitter, if it is stuck, the FOB does not transmit."

Since my FOB is working fine, I did not want to monkey around and try to remove the ball bearing cover......

Cheers......
-Al

 

Thank you all for the suggestions. It appears to be a bad fob. It doesn't have a removable cover for the 'ball bearing' but it's always rattled freely. I replaced the battery went & through the process of programming again, several times. Two things were apparent this time. One, the flashing light, never stops flashing even with the fob in the car. Second, when I proceeded slowly after progamming, I noticed the car just locks on it's own, whether the fob is near, far, battery, no battery, etc. It just locks after programming, after a certain period of time. My wife isn't too crazy about the lock/unlock without pushing a button feature & wants me to install a 'clicker' like I put on our 84, for the doors & hatch. Since I still have a couple of those kits left, I guess that's what I'll do

Where is the best place to get a wiring schematic of the car? Thanks, again!

 

There are some limited onboard OBDII diagnostics that you can perform that may indicate if your FOB(transmitter) is bad. I have done this on my '94, and the procedure should be the same for '95 and '96:

Quote from "theadmiral94" :

to display PKE DTC's (via the the blinking "passive keyless entry' lamp, the ignition key must be IN the ignition BUT in the OFF position, and then you can use the old paper-clip method and jump (ground) pin#8 (top right most) to a ground pin#4, remember #1 is top leftmost.

(Repeat: Key in igniton only, do not turn or start engine)

Unfortunately, there are only 6 as follows:

12 - receiver memory bad
13 - transmitter not in range
14 - non-valid transmitter received

15 - valid transmitter received
16 - passenger door buttton depressed
17 - hatch button depressed

As you will notice, the first 3 display 'current state' of the system, whereas the last 3 require a working transmitter.

FYI, the system does not store DTC's nor do they need to be cleared.

However, all that said, more often than not, the problems with PKE are either:

1. it's turned-off (see owners manual for turn-on instructions or my later post)
2. door switches are stuck/sticking/electrical malfunction (can use 'door ajar' or CCM diagnostic mode to test)
3. door key switch sensor is out-of-sync (use key to unlock door sometimes resets)
4. remote's internals are dirty (wake-up ball-bearing inside the metal housing is dirty) -- take apart gently and clean.

 

Thank you, again for the suggestions. No 'codes' are given. I tried both the key and also lock switch inside the car. Inside switch definitely turns the alarm on/off on lock/unlock as long as you hold the button on for 4-5 seconds. My 95 fob (& who knows if it's the original) has what looks for all the world like a little, metal led for the 'rattle' switch & I don't think it's removable cover. Doesn't look anything like the switch in your picture. I looked on the internet & boy these are expensive little transmitters. I buy remote kits in bulk 10 packs & pay $22.77 per unit. Once I get the wiring diagram located with VATS info & such, I'll just wire in one of my kits. It does seem like it might be a little annoying locking/unlocking every time you pass by it with the key in your pocket. Thanks all for your help.

 

You might try doing a search on this forum for installing after market systems w/factory PKE---most seem to regret doing it---take it for what you think it's worth. Personally my PKE still works great ,so I can't say what the issues have been with some of the members.

 

I'll agree with TWISTERUP on this.
You probably should do as much reading as you can find on exactly how the PKE system works.
Pretty good details in the owners manual
If you don't have one, you can download one here:
http://www.gmpartshouse.com/download...95corvette.pdf

The system in the C4 is unlike any other keyless entry system you've ever seen. That's why the fobs are so expensive.
There are no other fobs that will work with the C4 system.

You can turn this system on and off any time you want too.
When its working as it should, if the locking and unlocking bothers you (as in when your working around the car), just turn it off.

 

I do have the owners manual & had already tried everything in there before I went online to search for information. I was able to locate a factory service manual with all wiring schematics from our local dealer today. He was kind enough to 'loan' it to me. It looks fairly easy to work up a by pass & use one of my units. After I complete it, I will let you know how it works. I had an Altima with a fob to unlock & start the car a few years ago. As long as you had the fob with you, you jumped in & pushed a button to start. I never really like that, either. Besides, this is the wife's car & she wants a 'clicker', like her other cars. Have to keep her happy! Thanks to all again for your help/advice. Great folks on here.

 

Just an update on the PKE issue. I was bored yesterday so I was looking at the fob & thought I'd check continuity on the printed circuit board as I've run across issues with dip-soldered items before. It didn't show continuity on 2 circuits from the IC to their connecting solder points. Sure enough with my 8X specs on, I found 2 hairline circuit fractures, directly under (opposite side) of where the battery inserts. It appears someone got over-exuberant with installing the battery and 'cracked' them, though the board didn't show a crack. I just scrapped & ran solder over the breaks in the circuit & it works just fine, though it seems you have to be very close to the car before it unlocks it.

In regards to using the aftermarket system remote I mentioned, I had both door panels off this weekend removing non-factory tint & while I was in there, I connected the aftermarket unit to the factory door switch as a 'test' to see how it functioned. It worked fine & still set & un-set the alarm as the doors were locked & unlocked & it also started fine. I didn't hook up the hatch switch as I couldn't see any reason that it wouldn't function. Of course you'd want to trace these wires to the main loom & install the unit under the dash to prevent moisture & shock but it looks like aftermarkets will work fine. For now will see how the wife does with the PKE, since it's working. Thanks to all for your help.

 

Yes, the system does not have a very long range. If your walking very fast, you can reach for the door handle before it activates the locks.

Setting the doors to lock is what actually sets the alarm, so it's not really the PKE system doing that. Even if you used to lock button on the door panel, the alarm would still be set.

Thanks for updating everyone on what you found out.

 

Not to muddy up the waters, but if you were trying to lock the door with the button you may have turned the system "off". Is it possible it is really working OK?

Sorry, didn't read the latest post close enough. Sounds like you found it.

 

Found this post a bit late so did not get a chance to chime in. However got to say nice job.

You are not the first to find those hair line cracks in the lands on the circuit card as I have seen posts in the past with the same success.

But it’s always nice to have a spare FOB for times like this and diagnostic purposes.

 

I just changed the battery (somewhere I read that it's a 2430) and now it doesn't work. The battery that was in there was the thicker 2450. It looks like the 2430 should work, but nothing's happening. Did I waste 6 bucks on a battry that won't work, or do I need to go through the re-learning steps?
Thanks!

 

You shouldn't need to "re-learn" after putting in a new battery. Just get the correct one.

 

I should haave taken the device apart before ripping open the package with the battery in it! Once I got the correct (CR2450) battery, Everything worked. Thanks, Mark!

Paul