556s in cold weather
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=110405
Printed Date: May 18, 2024 at 11:02 AM
Topic: 556s in cold weather
Posted By: kgerry
Subject: 556s in cold weather
Date Posted: January 06, 2009 at 1:33 PM
I have read on websites that the Ford data style bypasses are better than the 556S style because they don't freeze up in cold weather.... what exactly freezes on this module? why would it be any different than a 556U? i have literally hundreds of 556U's out there and have never had any cold weather issues, yet i got a call today from a customer we used a 556S on a few months back who says it wont start when very cold, the OE anti-theft is kicking in....
what part of the 556S is actually affected by cold? the coil around the key? why is this any different than a regular 556U?
is there a fix to this problem short of ripping out the 556S and putting in a data style module?
-------------
Kevin Gerry
Certified Electronics Technician
MECP First Class Installer
Owner/Installer
Classic Car Audio
since 1979
Replies:
Posted By: KPierson
Date Posted: January 06, 2009 at 4:36 PM
What we used to do years ago (before the better bypasses were around) was remove the ring around the igniton and zip tie it around the key and then hide it really well under the dash. This completely bypasses the OEM security so you would want to get the customers permission to this. I would guess it has something to do with the frequency that the coil is tuned to. Weather has an effect on resistance and resistance plays a role in tuning coils. I have no actual first hand knowlege, but that is my assumption. It is obviously something wrong in the module itself as the OEM key never quits working! ------------- Kevin Pierson
Posted By: loneranger
Date Posted: January 06, 2009 at 4:49 PM
Not to be difficult, but weather has no affect on electrical properties. However, extreme(-300/+2M) temperatures do. What is more than likely causing the issue, is cheap component/s selection in the module design, where the component/s themselves fallout of specification at low temperatures. DEI engineers, I'm sure, are aware of such issues. Another likely cause, and very possible, is condensation on the tuning coil. If the coil wire insulation is breeched, condensation will short the coil winding.
Posted By: KPierson
Date Posted: January 06, 2009 at 6:18 PM
I'm guessing DEI would use the same quality of components for their entire line of modules (at least automotive range). I would also doubt the coil wire insulation would only be breeched on every 556S made and not any of the other transponder modules. From memory the modules quit working around 32 degrees or so. They've had this problem since 2001 or so, back when I was installing. It's interesting to hear they are still having the same issues this long after. And I do beg to differ about weather not effecting electrical properties - if you get a chance measure the current that it takes to energize a standard automotive relay. A relay I had sitting here initially pulled 127mA. However, the longer it stayed energized the less current it pulled. Why is that? After 20 seconds or so it was less then 125mA (this was on a regulated labratory 12vdc power supply). Voltage remained constant and current is a direct function of voltage and resistance, meaning the resistance HAS to be changing (94.48 ohms vs 96 ohms). I then threw the relay in the freezer for 15 mintues. It was around 17 degrees when I pulled it out. I energized the relay again and whoa, look at the current! 145mA! That's a coil resistance of 82.8 ohms. So, from going from ~65 to ~17 degrees the resistance of my admittingly cheap coil dropped >10%. This shows, undoubtedely, that electrical properties do change with weather changes. This little test can also be done with an ohm meter, but it's much more interesting to actually energize the relay to see the current change. This is because the coil is warming up, thus changing the resistance, thus changing the amount of current needed. ------------- Kevin Pierson
Posted By: another-kelly
Date Posted: January 07, 2009 at 12:05 AM
the story i got from DEI was that the RF pellet in the ford keys would transmit weaker when it got cold. the solution was to freeze the ford key prior to putting it into the 556u (or 556S, we just always used a U). then when you are placing the key in the bypass it may take a few attempts to find the "sweet spot" with the head of the key in the coil of the 556u. once i started doing that, i had no more issues with fords not starting in the cold
Posted By: chriswallace187
Date Posted: January 07, 2009 at 12:29 AM
I think it's Ford keys that are the problem more than anything else. The transponders don't reflect the signal back from the factory antenna ring, or the ring itself puts out a very low power. KPierson, can you tell me if this an electrically accurate description of how transponders work?
I've had similar problems with RF bypasses of all kinds on Fords(555F, 555S, 556S which I once left in my freezer overnight to make sure that the antenna would work right, and universal bypasses too). Used all those bypasses up, switched to data, and never looked back.
Chryslers, on the other hand - I've tested an install, holding the key 6" from the ignition, and the car recognized it just fine. No problems with their RF signals.
-------------
C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: KPierson
Date Posted: January 07, 2009 at 5:52 AM
In transponder systems there is a signal that is transmitted from the car to the passive key. When the key is close enough to the signal the signal energizes the chip in the key and the chip in the key transmits it's own signal back to the car. The key doesn't reflect the signal as that wouldn't really provide security. Each chip is given a statistically unique ESN and that is why keys have to be programmed to cars. With a transponder bypass installed the factory transponder ring isn't used as a transmitter anymore, just a reciever so I would assume the problem would have to be in the key, not in the ring. ------------- Kevin Pierson
Posted By: chriswallace187
Date Posted: January 07, 2009 at 12:01 PM
KPierson wrote:
In transponder systems there is a signal that is transmitted from the car to the passive key. When the key is close enough to the signal the signal energizes the chip in the key and the chip in the key transmits it's own signal back to the car. The key doesn't reflect the signal as that wouldn't really provide security. Each chip is given a statistically unique ESN and that is why keys have to be programmed to cars.
With a transponder bypass installed the factory transponder ring isn't used as a transmitter anymore, just a reciever so I would assume the problem would have to be in the key, not in the ring.
OK, that's definitely better than I had described it. I'm still trying to remember exactly the electromagnetic means of transmission though. Like if it's analogous to radar, sonar, or something like that.
I would disagree that the factory ring doesn't function as a transmitter when using a bypass, though. Isn't it really doing the same thing it would with a key in the ignition?
The obvious difference is that the key's mounted remotely inside the bypass, or the bypass consists of a transponder chip, but I don't believe that in either of those cases the transponder is receiving any electrical power through the wiring going to the remote start. The bypasses we're talking about here use a relay to complete the inductive loop (right phrase again?) so that the transponder can receive the RF signal and return its unique ESN. ------------- C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two
Posted By: loneranger
Date Posted: January 07, 2009 at 10:13 PM
KPierson wrote:
And I do beg to differ about weather not effecting electrical properties - if you get a chance measure the current that it takes to energize a standard automotive relay. A relay I had sitting here initially pulled 127mA. However, the longer it stayed energized the less current it pulled. Why is that? After 20 seconds or so it was less then 125mA (this was on a regulated labratory 12vdc power supply). Voltage remained constant and current is a direct function of voltage and resistance, meaning the resistance HAS to be changing (94.48 ohms vs 96 ohms). I then threw the relay in the freezer for 15 mintues. It was around 17 degrees when I pulled it out. I energized the relay again and whoa, look at the current! 145mA! That's a coil resistance of 82.8 ohms. So, from going from ~65 to ~17 degrees the resistance of my admittingly cheap coil dropped >10%. This shows, undoubtedely, that electrical properties do change with weather changes.
What you are witnessing is the mechanical properties of the conductive material(copper) as it changes through temperature. Copper has a positive co-effcient. It will expand and contract, through rising and falling temperatures, respectively. This causes the coil inductive properties to increase and decrease, as the coil shrinks and expands, respectively. What you saw with your meter was the inductive properties being influenced by the capactive properties of your meter, as well as your power supply. This manifests itself as a reactive load and not purely resistive. Note: My statement "However, extreme(-300 F/+2M F) temperatures do." should be taken purely as an example. I have no idea at what tempreature copper become a super-conductor, nor when it ceases to acts as a conductor. They're certainly extreme, in that they don't naturally happen here on earth.
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