Harbor Freight sells reasonably priced code readers for 1996 and later cars. What do I use for my 1995 850 and where do I buy it? Thanks.

You don't. there is a box under the hood that you access to read the codes. open your hood. do you see your windshield washer bottle? next to it are two black boxes open the covers. they will be marked A and B. both of them have six holes, each numbered. now, ignition is off, unclip the test lead from the side of the unit. looks like a peg and has a wire coming out of it. insert that into socket six (6) on the A box. get a piece of paper and a pen and be ready to write. on A you will see a red LED light and a button. the codes flash on the LED. there is a pause between each number, ex: blink blink blink........(that is the pause)blink blink the code is 32, get it? now the lead is in, switch on the ignition, press the button on A once, wait for the LED to flash. as it flashes write down the number sequence. these are for any codes for the ignition stored in your ECU. press the button again and write down that number, etc. unitl the first sequences is repeated to you. now switch off the ignition. if code 1-1-1 is flashed, there are no codes stored in the ECU. that is for the ignition portion of the ECU now we will do the fuel injection portion. now insert the lead into socket 2 of A, switch on the ignition press the button and write down any codes. again, when the first sequence is repeated, you are done. turn off ignition.again, if 1-1-1 is shown, there are no codes for the fuel injection. in both instances, if 1-1-1 is shown, you are in the clear, with the ignition off, remove the lead and reclip it to the side of the module and close the lids. remember, if there are codes, they have to be deleted before you finish because they will always show up, to delete them for the fuel, keep it in socket 2, turn on ignition and press the button for a count of five. let go of the button and after like three seconds the LED will light. press the button again for a count of five and let it go,the LED will go off. turn off ignition. to check and make sure that they have been deleted, repeat with the button press test. when it shows 1-1-1 all is clear. for the ignition test, turn off ignition, put lead into socket 6 of A and press the button for a count of 5, etc. etc. when that shows 1-1-1, you are done. now have a beer or three and fondle the old lady, not your wife, the old lady next door. :grin: just don't call me from jail. good luck. if you need help, just ask. later-

My 95' 850 T has both the self-diagnostic unit under the hood and the OBD II plug on the centre console. Do you think i am missing out on a lot of information by using the self-diagnostic unit? Would it be worth buying a reader?

i would get to a pepboys, if you have one in your area, or a napa, one of the bigger chain stores. they usually offer a codes reading service. have them read the codes through the OBD II port and see if anything comes up. do you have outstanding codes right now? if so, now you will see if it does read through there also. if it does, then buy one. it is worth it in the long run. it pays for itself. you can go for the lesser model, the ones that I have seen do not erase the codes and they just give the 3 number designation. the higher end ones give the description and erase and make coffee, too :grin: seriously, check it out then decide from there. good luck.

Yours must be a later MY of the 95. Well if you bought a reader you wouldn't have to read completely through the Greeks long and confusing explanation of reading codes. That in and of itself is reason enough to buy a reader. :rolleyes: B)

Ya, i guess you're right. A descent scanner would pay for itself in no time! I wonder if '96 and later models have both aswell? My production was late '95 which would probably be on the lot as a 96' model year, which i beleive is the first year for OBD II

Come on now, Ya can't knock the self-diagnostics. I love the black box!!!

GreekMason you are a most helpful guy. I followed your procedure and nothing happened at all in hole #6 for ignition, but it worked in the #2 position and gave me a code of 121 which I reset. I was asking about this because since I tuned up my car the check engine light has been on and I want to reset it. I had crossed the spark plug wires because I didnt have a torx set to fit the sparkplug cover and couldnt see both ends of the wires. I believe that this is the cause of the light coming on. I may try disconnecting the battery for a while and find out if that will reset it.

Update - I have found the info covering fault codes in my Haynes manual and I have concluded that I must have a Motronic system as I get no codes from position #6. Also I saw that code 121 indicates a faulty or missing Map sensor. I went out and looked at it and saw that the MAP sensor is indeed not present. I hope that my ignorance can be overlooked as the Volvo is quite a new animal to me. Can anyone advise me how to get the check engine light to turn off?

No the 96 and up only used the OBD II system.

I am happy to report that I just successfully turned off both my check engine light and the service reminder light. Many thanks to GreekMason for pointing me in the right direction. I am new at this and probably appear to be pretty slow to the experienced Volvo owner but I do catch on eventually. I need to do whatever work myself that I am able to do given the crazy prices people are trying to get for labor and parts for Volvos.

If you go to Matthews Volvo site, there is a link that enables you to download the complete Volvo 850 manual - by comparison, the Haynes repair manual look like a kindergarten primer.

It contains everything, and more, the average 850 owner needs to know about keeping their vehicle on the road.

:clap:

Thanks Volgrrr. That is a good tip. I will definately do that. Thanks again.

see, sometimes I am helpful and to think that people say that I spell so badly. i wrote that whole thing witha bottle of jakc dnalies in my hand while eating a opastrmi samwich. :grin: