I'm being haunted by an 03 S40 and recurring fault lights. Is there a way to reset the codes without a reader? I've tried removing the battery cables and briefly touching the cables...that did nothing, so I took off cables and clamped them together over night - still showing codes afterward.
Do I have to find someone with a reader to be able to reset, or is there something the shade tree mechanic can do to clear them?

 

Nothing you can do on your own.

Also, without fixing the problem(s), the codes are just going to come back.

 

Either $$$ (dealer visit) or time (DiCE VIDA). A few trouble lights will go away on their own if you fix the original problem, but how will you know what to fix?

 

You need a reader to clear CEL's. I bought a cheap one off of Amazon for <$20 and it works great for giving the codes and clearing the CEL. I have a recurring CEL, P0420, for the Cat... not worth the $$$ to fix, so I just clear it out once a week.


Local parts dealers usually have readers and will give you the codes, Autozone will even print them out for you. They are not suppose to clear the codes for you... but ask nicely and explain that Yes, you know clearing the codes isn't fixing the problem... and they will usually clear them for you. And sometimes when you are not sure if something you replaced/fixed actually solved the problem its useful to clear the codes and see if they come back.


Amazon link to the OBDII reader I use:

 

The cheap readers only give you the "generic" codes. A Chinese clone DiCE / VIDA unit, for about the price of one dealer "We'll look at it" visit, will give you a complete Volvo trouble codes, a factory workshop manual, access to all stored trouble codes, and the ability to monitor operating variables and directly set some values. The only thing you won't be able to do, AFIK, is download and install software.

 

Just got my Harbor Freight catalog - they have a reader on sale for $69 I'm thinking of checking out. No job is worth doing unless there's a chance to buy new tools. :-)

BTW, that's one thing I love about my '95 850T. I can read codes via its built in diagostics panel. Not sure why they did away with that (conspiracy to push owners back to dealers?)

Livens - since you're not planning on replacing the Cat on your car, have you looked into using an O2 sensor spacer? this keeps the sensor out of the immediate exhaust stream and will allow the system to operate and not throw a code...

 

I have, sort of. I saw the "CEL Boss" O2 Spacer from iPd online, $30... I'm cheap so I found a $5 one at a local parts store, it was meant to be a spark plug extender I think, but the threads were the same. It did not solve the problem . Then I looked at the iPd closer and it is almost twice as long as the one I used... When I have the extra $ I do plan on ordering one.


I agree with mf70 on the Chinese clone DiCE / VIDA units. If you are going to spend $70 on a Harbor Freight special I would get the Chinese clone DiCE / VIDA unit instead for a little more $. The code readers only get you so far... really just enough to start throwing parts at the problem sometimes. I've been lucky so far and all of my CEL's have been pretty straight forward... code for a miss in cylinder 3, google said check my coils, yep it was the coils

 

I first did the spark plug extenders. Two of them placed together. I had to drill out the center portion a bit as it was just a tad too small for my Bosch O2 sensor. Next I bought the IPD Cel boss and found it worked great right out of the box. It's much thicker and just better built than the cheap spark plug extenders.

mt6127 - Remember 1995 was the wierd year of OBD1.5 where OBD1 was being replaced by OBD2 but the standards weren't out yet so everything made that year has it's own thing going on. I have a 1995 Chevy truck and it doesn't comply with OBD1 or 2.