Engine 850: B5234T/2.3/20v/T5: home made code reader

[Lmason]

if a 12v led is placed from link 4 to link 16, then a wire from link 3 to the negative side of led should reset the ststem??

[bob13]

That sounds about right just put wire into pin 4, for 5 + secs see if led lights up take it out then put it back in for another 5 secs. Just be carefull not sure how the ecu would take a short or a wire in the wrong place. Hope it works for you.

You may not even need the led just go from 4-3, 5sec + then take out then put it back in. Dont think it would do any harm, as the led is only a visual device. Just have to guess that the led would have lit up. If it doesnt reset try led, if not read codes using this method. Good luck hope it works just take care dont wont to do more harm.

[Lmason]

hiya bob.
i worked the diagram to be just that. making it simple, putting a link between pin 3 and 4 for approx 5 seconds. as i dont have climate or cruise control. and as you said, the led is just a visual of what it is doing.
i will let you know if it works.
i have been told on the vauxhalls, the pin to short to ground is no. 7, so the principle is the same.
i just didnt know which pin on my volvo.
its supposed to work on these early models, but on 2002 onwards models, it has to be a code reader. i have one of these code readers, costing £150 quid for my previous car, but it dosnt work on mine.
thanks for the info, and look up the thread later.
i dont think i will get it done tonight, but maybe tomorrow.
cheers

[Lmason]

tried linking pin 3 and 4 with a paper clip, but did not clear codes. think i may have to goto dealers. volvo aint that bad, they only charge 23 quid unlike vauxhall and ford which charge £45

[Chris_Rogers]

You need to read the codes before you can clear them so just linking pin 4 to 3 will not work.
The resistor you need can be any value between 1000 and 2000 ohms and any wattage, the smaller the wattage the smaller the physical size and cost of the resistor will be.
I should think you should be able to get the parts from any TV repair shop.

[Lmason]

yes i see what you are saying. i wasnt sure which size resistor but now i might order from maplins . just out of interest. usually garages want the job to replace the faulty part if there is one. might save me a bit coin

[bob13]

To be honest i didnt think the light would go out because i am sure the lite will go out once the fault has ben fixed but i may be wrong. But worth a try. The code reader just clears stored code. Is worth making the reader though always handy and doesnt cost much, in fact i brought the proper plug and that cost me more than all the other bits. Good luck with the fault hunt Bob....

[Lmason]

i have just ordered the bits for the tester, including a nice little box. i will make it up and test it out when assembled. bob, where did you get the plug from? i hope my engine management light is just a case of resetting, if not, and it reads a fault, indicating where or what, then i can give it a go in repairing myself. i will keep you posted in the next few days on this thread. the light did come on when i unplugged the maf sensor, so just hopeing it only needs a reset.
ps i have a haynes manual which tells the codes of the earlier models with the underbonnet diagnostics led, is the readings the same? ie the amount of times the led flashes, to indicate a specific code, as there is alot of indications.
cheers
les

[Jod T5]

Originally Posted by Lmason

i have just ordered the bits for the tester, including a nice little box. i will make it up and test it out when assembled. bob, where did you get the plug from? i hope my engine management light is just a case of resetting, if not, and it reads a fault, indicating where or what, then i can give it a go in repairing myself. i will keep you posted in the next few days on this thread. the light did come on when i unplugged the maf sensor, so just hopeing it only needs a reset.
ps i have a haynes manual which tells the codes of the earlier models with the underbonnet diagnostics led, is the readings the same? ie the amount of times the led flashes, to indicate a specific code, as there is alot of indications.
cheers
les

if your light is maf sensor related it should automatically be reset if the ecu is removed overnight....
if it still does not go away you have a permanent fault that needs resetting
the flash code reader is a very basic electrical device, one that can be imitated with a 12v light and some wire....if you dont have a bulb a multimeter will do.....
cheers
jod

[Jod T5]

just a thought, you are aware that after joining 3-4 together for 5 seconds then remove, the light will flash again...during this flash you must rejoin 3-4 to finalise code deleation.....
cheers
jod