AUTO LOCKSMITHS
Transponders: a beginner’s guide
While it would be impossible to cover every aspect of
transponder technology, Ravi Kotecha of Autowave makes
a start with some elemental information on how to select
the right type of transponder for the job at hand…
First, what is it?
memory function in some
vehicles (where each key saves
settings such as seat position,
illumination etc).
I always advise my
customers to program where
possible and if they are unable
to program, clone as a last
resort.
Transponders - short for
transmitter/responder -
were introduced in 1995 to
increase vehicle security;
a small magnetic-coupled
transponder with non-volatile
memory (can store data
without constant power).
What happens when
a programmed
transponder meets
the ignition?
When the ignition is turned
on, the transponder works
as an inductor and sends out
an electronic field, the coil
uses this energy to power a
small electronic chip that then
transmits the logic/data to
the vehicles ignition receiver;
which then sends a signal to
the immobiliser and/or the
dedicated unit responsible for
allowing the car to start after
verification of a working key.
There are various
manufacturers of
transponders:
• Texas (60-70,4c)
• Megamos (13,48, 48AES)
• Philips (33, 40, 41, 42, 44,
45, 46 (hi-tag2) id47(hi-
tag3))
• Sokymat (8e)
• Temic (11, 12, 8c) (all
Temic chips are fixed
code).
Generally, in our industry
there are three types of
transponder chip that we use;
glass, carbon and on-board
chips.
With glass type and
carbon type there are also
two further sub types,
72
cloning transponders and
programming transponders.
On-board transponders
which are soldered on the
PCB are usually programming
transponders, this is because
on-board transponders are
used on remotes where the
central locking function is
programmed at the same time
as the immobiliser.
Programming transponders
(glass, carbon and on-board)
are coded to the vehicle using
either the OBD port or via
EEPROM/MCU methods
and is the best way to code
a transponder to a vehicle,
this is because the vehicle
immobiliser is aware of
the new transponder being
paired and identifies the new
transponder as different to
other transponders already
programmed.
A programming transponder
must be prepared with the
correct logic which is suitable
for the vehicle, for example
if you are programming to a
Vauxhall Corsa 2004 you will
need a PCF7935 ID40, you can
either purchase it as a PCF7935
ID40 or you can simply
purchase a blank PCF7935 and
write the logic using a device
such as VVDI or Tango; this
saves having to stock lots of
different transponders.
Cloning transponders are
used to do just that; ‘clone’
the existing data on an already
programmed transponder
using a cloning device such
as VVDI Key Tool, Handy
Baby, CN900. The benefit of
this method is that it is quick
and easy, it does not require
any knowledge. There a few
downsides to this including
the need for an existing
programmed transponder, the
risk of future programming
causing the transponder to
be accidentally deleted and
the loss for the vehicle key
There a various
manufacturers
of programming
transponders such as:
• Texas (4D ID60-70….)
• Philips (7935, 7936, 7937,
7939….)
• Sokymat (8E)
• Temic (11, 12, 8C…)
• Megamos (13, 48,
48AES…)
Most cloning device
manufacturers also
make transponders,
such as:
•
•
•
•
XHorse
JMD
Silca
IEA
Some devices will also
allow a cloning transponder
to be used as a programming
transponder which is
becoming more and more
popular as aftermarket
remotes and keys are being
used.
Autowave stocks a full range
of transponders available
at www.AutoWave.co.uk or
simply pick up the phone and
speak to myself or one of my
colleagues on 0115 8377972
and we will be happy to give
you more information.
JUL/AUG 2019
locksmithjournal.co.uk
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