the check engine light came on last night
has been 25 to 35 degrees farenheit here
the car has been running well-always started and let idle until temp is up
but now am trying to filter throught the brickboard and figure out what people are talking about in reference to "codes"
where is the magic code box in a 940? and where in the green book is it explained?
any help would be greatly appreciated
the advice on here about the bulb sensor failure relay saved me a bundle when i replaced it my self
-the mechanic was dumbfounded when i told him what i did on the advice of those on here

From a shade tree amateur, checking the codes sounds complicated but it’s easier than baking a cake once you plan a step by step process. Print out the instructions or copy it to a word processor and highlight the steps after you determine which of the two ignition/fuel injection system you have. I really don’t think you can break anything. The two black OBD boxes with removable caps are located on the left side fender wall slightly behind the power steering fluid reservoir. The OBD boxes are labeled A and B under the caps. If you think you made a mistake in pushing the button just repeat the process.

Herein lays (or lies) the problem. There are sometimes errors in the codes that are given. I (meaning me) would get the code(s), clear them and wait for the car to reproduce the codes again. Post back with the results.

BTW, few mechanics wouldn’t be dumfounded by the information in the FAQ and the amateur and professional experience on this board.
--
Tom F. Couple of Volvos Mods, RainX & cup holders.

ok so now i know where the boxes are
there appear to be wires running to holes 2,3,6 in box A
and in #2 in box B
with the engine off butnot running but in the on position i push the button with the tester in #1 or do i run through all the holes in the series?

actually my last question was a stupid one
what i really would like to know is what is associated with holes #1-6 in box A and B

Dear Colinaj,

Good p.m. and may this find you well. The only "stupid" question is the one not asked.

A1 = Transmission
A2 = Fuel system
A3 = ABS (Anti-Lock Brake System)
A5 = TCU/CEM (Turbocharger Unit)
A6 = Ignition System

B1 = Climate Control ECC 850
B2 = Cruise Control
B5 = SRS (Supplemental Restraint System [Airbag/Seatbelt tensioners])
B6 = Power Seat

Not all of these functions will be "enabled" on every vehicle.

Hope this helps.

Yours faithfully,

spook

Dear colinaj,

Good p.m. Here's how to access the codes.
(a) With the ignition completely "off" (key not in it), remove the box cover and put the probe (in a recess in the side of the cover on Box "A") into hole "2" (Fuel System).
(b) Turn the ignition key to "ON", but do not start the car (the instrument "idiot" lights should all be lit)
(c) Press the button on top front of the Code reader and hold it down for one second
(d) Release the button
(e) Wait about two seconds. You should then see, at about 1-2 second intervals:
"flash" - "flash" - "flash". If so, everything is find. Repeat to confirm.
(f) Turn the ignition key to "OFF" and move the probe to hole "3" (ABS). Do the same as in (b)- (e).

Repeat this, for every position, for which there is a receptacle.

1-1-1 means no problem.

Any other result signals some "abnormal" condition. See the FAQs for the common malfunction codes.

If some code turns up, that is not covered in the FAQs, post it. I have a pretty comprehensive list of these codes, published by Volvo in its Pocket data booklet - Cars, 700,850,900 (1991-1996).

Hope this helps.

Yours faithfully,

spook

Dear Colinaj,

Good p.m. In my haste, I omitted:

A7 = Combined Instrument Panel

After 1994, the diagnostic functions were shifted to a receptacle inside the passenger cabin, from which the codes can only be read with a hand-held "reader".

I regret the omission.

Yours faithfully,

spook

Spook, thanks for jumping in.
I think you meant to say: After "1995", the diagnostic functions were shifted to a receptacle... at least in the 940.

--
Tom F. Couple of Volvos Mods, RainX & cup holders.

Dear Tom,

Good p.m. and hope you're well. You're 100% correct. I sit, corrected.

Yours faithfully,

spook

The OBD control unit is under the hood on the driver's side shock tower. It is easy to check the codes and to reset the codes. Everything you need to know about how to do it and what the codes mean is listed in the 700/900 FAQs:
http://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

Hope this helps.

Mike
--
Mike Brown Greenville, NC 1996 965 113K 1994 940 135K 1986 244 137K