My Service Light on my 1995 850 Turbo continues to be on for a second or two, then goes off for a second or two, then back on, back off, etc. etc. etc. I reset the light via the OBI diagnostic module. I start the car and the service light is off. When I then turn the car off and start it back up - the light then starts flashing again.

Any thoughts.

code it, code it now! the on board monitors so much on that car its scary to find out, mine did that ritebefor the mas flow went out. may not be your issue, but the computer knows, do you have a hanes manual, it has decent list of code identity.
good luck :grin:

Should I pull all the codes on each of the OBI A and B slots? I had the engine light come on (see my other topic) and pulled a 231.

i replyed your answer ther too. but yes do a complete check, get all codes, go two rounds on the code count, just to make sure you get a complete check.... try to get your DLC plugged up too. use a Actron Scantool. your engine management computer is not forgiving of new big gain mods, it will shut you down to save its buddy the t5. big friends they are. :lol:

davidemir1994-850-gst,

I pulled my fault codes from the OBI Diagnostic and got:

A1 - 114 (????)
124 (????)

A2 - 111 (was 231, until I reset it)

A3 - 444 (???)
213 (???)
214 (Engine RPM sensor signal absent)
424 (????)
443 (????)
142 (????)

A5 - nothing

A6 - nothing

A7 - 111

B1 - 325 (ECU Memory Loss)
417 (???)

B2 - 122 (Intake air temperature sensor signal absent or faulty)

B3 - Nothing

B5 - 111

B6 - Nothing

B7 - Nothing

This can't be good. I went through them twice as you recommended. My Haynes manual only seem to have a couple of them. The physically seems to run great if it starts (which is usually 95% of the time). Where do I start?

first off that rpm sensor sends info needed for proper management. fix that. it will help on the rich lead code. if you cant get a complete list of code identity out of your hanes book the you can get a list complete from your local dealer, my advice to you is to get the list, go to an auto parts store that has access to a reader to double check your codes. fix your bad sensors first, sensors go bad unnoticed till you need that info. 850s are computer driven cars, no signals means bad performance or none at all. i have a dealer service tech book at hand, i will look up your codes and get back two you today :thumbsup:

you can't use a scantool on your car. you are obdI, no scan tool. any 1-1-1 code means nothing there. now, sensors first, most times when you change the sensor, it will clear up any probs that are associated with it. if there is a real prob it will reoccur. your service light is just that, a service light. it reminds you that you need to have a service call. be it a tune up, oil change, etc. mine comes on and goes out after a minute or two. when you have your car serviced, have them erase it. it can be done by erasing all on the obdI ports. no worries. now, if a hatch opened on your dashboard and a little swede popped out with a suitcase and he jumped out your window, then you worry. or stop drinking. :grin: no worries, do the sensors and erase all the codes. see what comes back.

Quick question - when I pulling fault codes - should i be pulling them from each of the sockets in the A and B, as I've noted above? I'm looking at some Volvo literature that covers fault codes (which seems to list every possible code), but it only says to retrieve them from Module A socket 2.

each socket and box control various different items. pull them from all. that way you can be sure that you have tracked down everything. box
B will tell you about your a/c box A has the fuel injection also in a different socket of A it will give you the general fault codes. you have to be sure which socket it came from and which box you are looking at. to answer your question, socket 6 Box A is for fault code read-out. how did you try and reset your service light? which instrument panel do you have? vdo or yazaki?