Most vehicles display thier Petrol and Diesel Engine, ABS
Brakes, Airbag and Auto Transmission codes by flashing a
light on the dashboard of the car.
One thing that you can use as a jumper wire is a "Steel
Paper Clip" that has been straightened out as shown
in the diagram to the right. It must be a steel one, and
not have any plastic coating on it.
Using a paper clip
or a piece of wire as a jumper wire is PERFECTLY SAFE.
Using jumper wires to flash codes has been built in by the car
manufacturers to ensure people without a Scan Tool or Code Reader
can still diagnose the vehicle faults by reading the codes.
Simply follow the step by step instructions which clearly
show you which terminals on the diagnostic connector to
link, and then insert the Paper Clip into those terminals.
The picture to the
right show a typical example of bridging 2 terminals of
a diagnostic connector to start a Check Light flashing on the
The website pages will now generally ask you to turn the Ignition
A Check Light
on the Dash will now begin to Flash as shown in the diagram
to the right.
By using the code timing information, you can now
understand the pattern of the light flashes, and you can write
down the code numbers as they are flashed in sequence.
You can then enter the code numbers into
the final Codes Screen to get the code description
Using an LED Tester or Voltmeter to read the codes
Some vehicles such as pre
1998 Mitsubishi's and Hyundai's, plus some Kia and Mazda vehicles do
not display codes on a flashing dash light. These vehicles give thier
code signals directly from the diagnostic connector. You will need to
use an LED tester or a Voltmeter to read the codes from these
If you don't
have a voltmeter or an LED tester you can easily make an LED tester
for under $1, as detailed in the steps below.
How to make
an LED tester to read the codes for less than $1
Solder a 10K ohm resistor on to the positive (longer leg) of an LED.
You need the 10K ohm resistor to limit the current draw from the vehicles
diagnostic lines. The LED will still be bright enough to see flashing.
Solder one wire onto the bottom of the resistor. Solder another wire
WHICH IS SLIGHTLY SHORTER THAN THE FIRST WIRE onto the remaining LED
leg. The Longer wire is your Positive (+) wire. You should now have
something looking similar to the picture below. This basic LED tester
will work perfectly well, and allow you to read the codes with the Manual
If you choose
you can now heatshrink the two LED legs and add Aligator clips to make
it easier to connect to some of the vehicle diagnostic connectors.
To use the LED tester simply connect it to the vehicle
as per this websites instructions. You may need to try the LED
in both directions to get the correct polarity to make the LED
flash. This WILL NOT cause any problems, as it simply won't draw
ANY current in one direction (LED off), while in the other direction
it will be ON or flashing.
By using this websites code timing information,
you can now understand the pattern of the LED light flashes, and
you can write down the code numbers as they are flashed in sequence.
You can then enter the code numbers into the Code
Screen to get the code description (code meaning).
How to use a Multimeter to read codes
|You can use any standard digital multimeter to read the codes.
It can be a very low cost, simple meter. It only has to be able
to measure 0 to 12 volts. You can use an Analog Voltmeter, however
you need to make sure it has an internal resistance of at least
10K ohms to be safe.
|I find that if you have an Auto Ranging digital multimeter, that
it is easier to set the voltage range manually (if possible) to
a low range (say 10 volts) so that the screen goes between around
zero volts up to OL. This also means if your meter has a bar graph
on the bottom of the screen, it will move right across the screen
and back making it easier to count the code output pulses.
|Please note: A digital multimeter probably wont show exactly
zero volts when connected to the car diagnostic terminals. This
is OK, as you are simply looking for a major change in voltage.
The car code output systems will swing between either approx. 0
and 5 volts, or approx 0 and 12 volts.
Other Things That Can Help You With Auto Repair and Manual Code