I have a 95 940. The car has 135k miles on it. It's in good shape. In the very cold months it idles erraticly while it is warming up, but when its warmer outside it doesn't even do that. There is also a rattle underneath that sounds like the heat shield on a cat is loose.It used to have more power, but at 135k it is getting a little tired I imagine, but it runs smooth as silk.

When I start the car the service engine and CEL lights come on. The service engine goes out after a few mins but the CEL stays on all the time. The car runs fine. It's due for inspection so I have to get the CEL corrected. I don't have a code reader. Any one recognise the symptoms? Any ideas what might be causing the CEL ?

Also, do I need an OBDI or II reader for this car, and which is considered the best ?

 

The OBD1 system and diagnostic box are built into the car. The owner can read the codes himself without any other equipment. OBD11 requires a code reader to read the codes.

OBD1 should be on your car as OBD11 was fitted to cars from the '96 model year. The diagnostic unit is in the engine compartment behind the left strut assembly.

Instructions are attached:



[IMG]local://upfiles/4491/19BD88E0E04C4BC8BE3992AF61F83A88.jpg[/IMG]

[IMG]local://upfiles/4491/4CA6EA19CD7E4B1893BF5E8E34102F51.jpg[/IMG]

[IMG]local://upfiles/4491/D0584A8C5D294D118404E9F29FBF795B.jpg[/IMG]

[IMG]local://upfiles/4491/218666F9446F4373B550C7AF45EDF47A.jpg[/IMG]

[IMG]local://upfiles/4491/F5C60D5E63184BEF890FBFB6813BF710.jpg[/IMG]

 

Thank you for the information Bill.

 

OK, I checked the codes and get a 2-3-2 Lambda Adjustment code. Ignition is clean and feeds back 1-1-1. For the2-3-2 code it says to check intake manifold and check fuel pressure. The manifold seems fine, in fact a new manifold gasket was installed last time the CEL was on as the garage said there was a leak. Checkedthe manifoldlast night and it seems fine. I do not have a way to check fuel pressure, but the car runs fine.

The idle surges when it is cold outside, but it does not seem to do it when it is warmer than maybe 40F out. There is no fuel smell or anything when it does this. There is a rattling underneath like a loose heat shield, but I guess it could also be the cat rattling. I haven't really checked it out. Other than that, the only sign of anything being wrong is the CEL. The car doesn't have the power it used to, but it also has 130k miles on it. Cat is still original as far as I know.

Anyone have any ideas what this problem might be? Is it possible the fuel filter is dirty? Is it possible the cat is clogged and the engine can't adjust sufficiently? Should I clear the codes and see if it comes back ?

 

Have you cleared the code? The CEL will stay on until it is cleared.

The rattling you hear may well be a heat shield. I have owned several Volvos over the years and every one has had a rattling heat shield. Of course it could as well be the cat, they don't live forever even though they are supposed to have 9 lives (different cat?).

Symptoms can include rattling and loss of power, sometimes total loss. I have seen fitters check the cat by giving it a good shake but I am not sure that this proves anything.

How long is it since the fuel filter was changed? Some are never changed until the car grinds to a halt.

 

No, I did not clear the code. I will try that tonight and see if it comes back on and issues the same code.

The fuel filter may be quite old. If it was changed,the last timewould have been probably a year ago this time, when we were havingthe cartuned up for inspection.