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How to make a Flash Code Reader, for Dummies

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Old Nov 9th, 2009, 17:46   #1
Jod T5
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Default How to make a Flash Code Reader, for Dummies

It has recently been suggested to me that the flash code instructions previously posted do not work...

They Do...

The reason in the majority of cases why you cannot get them to work is beacause you have not followed the instructions correctly..The balance is due to some wiring issues with your "obd2" socket and that it does not work on some 850R' manuals which i suspect are 4.4 motronic and not bound for the USA market.. .....

Cars that give flash codes are:
850 and 70 10 Valve...
850 2.3 T5 (4.3 Motronic)
850 Jetronic (20V)

Late 850 20V N/A and LPT running 4.4 Motronic, and all non 10V 70's do not produce flash codes. They are OBD2 complient....

Common error areas are highlighted....

First go to Maplin and buy a 12Volt LED, a normal bulb will not work...Part number is CJ63T in red 0.49 inc
Buy a meter of Burglar Alarm cable, Part number is XR89W 4 core 0.59
Have some electrical tape, wire cutters and a paperclip handy......

Establish that you are aware that the LED has one leg longer that the other..This indicates that the longer leg is the Positive (+) side and the shorter the Negative (-) side... You may want to test your led works, it should light off of a PP3 9V battery normally found in household fire detectors. Dont forget to replace it after....

Cut the sheath of the Alarm wire and remove three of the lengths of wire. It may be useful to reduce the lengths to a shorter size...Strip 20mil of cover off each of the six ends....You will need to be able to identify which wire is which. I chose Red as + to LED, Black as - to LED and Yellow as my dipper...

Using the Wire-cutters make three lengths of pin and attach one end of each to both your + (Red) and your dipper wire (Yellow)...Join the other end of your dipper wire (Yellow) to the end of your - wire (Black). Join this combination to another paperclip pin..You can now join the other end of the + (Red) wire to the longer leg of the Led and the other end of the - (Black) wire to the shorter leg of the Led....

Emissions laws mean all modern cars have a OBD2 socket. The 850 is no exception and despite the fact it is very non-obd2 complient you have to use the socket to extract the Flash Codes... Flash Codes are not OBD2 codes...
The socket is situated under the coin rack, next to the Cigar lighter...

The socket is a 16 hole affair and the numbering is as follows...

Insert the Red wire (+) paperclip into port 16...
You can now check your LED is working by inserting the Black (-) paperclip into port 5. The LED should light. It should also light by replacing the Black (-) paperclip for the Yellow dipper into Port 5...
It is best to have the LED in a place it is easy to see. It can be taped somewhere or the cassette opening on the radio provides a decent enough home...

Remove all wires from port 5

Leaving the Red (+) paperclip in port 16, insert the Black (-) paperclip into port 3...You may see the LED light dimly...Turn the ignition to Pos 11 (with the warning lights on the dash, on)...If the LED was previously dimly illuminated then it will go out...
Place your Yellow dipper wire into port 5 for 2 seconds and remove....During the time the dipper is in port 5 the light should illuminate...

Count the flashes, taking the pauses into account...

Dum Spiro Spero
VOC 20419

Last edited by Jod T5; Jul 4th, 2010 at 09:41.
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