Is there a way to manually reset the engine light?

 

No there isn't I stated that in your other post about the same thing.

 

Autozone will reset it for you, there are many mechanics out there that will do it for free, it dosent mean it will get rid of the problem tough.

 

autozone has stopped providing OBDII services because of some legal thing. So I doubt they will be able to reset it for you. Maybe if you pay them

 

Hi,

What codes would you expect if you have a problem with a catalytic converter? If I am getting codes all linked to Heater Control Circuit, is there a best to the worst scenario? If I am told the sensors [which another mechanic replaced] aren't "active" what does that mean? Thank you very much. Diana

 

The O2 sensors have pre heaters in them that can go bad. There is also a fuse for the O2 sensor heaters normally and there is a fused heater for the pcv system on some cars.

So worst scenario - you have to find someone who knows what they are doing to fix your car.

A catalytic converter is a ceramic honeycomb structure blocking the flow of the exhaust. The exhaust is forced through the tubes of the honeycomb that are coated with platinum and rhodium - as the gasses (co, hc and o2) pass those precious metals - they change into co2 and h2o. If that does not happen - the rear oxygen sensor will detect too much free o2 left and set a cat efficiency code.

 

Thanks for responding. There is one Volvo dealer near me. Very expensive and not very friendly. It annoys me. Why don't other mechanic shops know much about Volvos? I know they are a European car, but aren't many cars on American roads diverse? Few are made in America. Firestone is bad too, but they don't claim to be able to fix Volvos. Don't exactly know what to do because everyone is afraid of the unknown--I tell them to check engine light is on and what I was told, but it's not clear and I'm not sure accurate. I have bought several O2 sensors, but another mechanic said the sensors were not "active" so I don't know what that even means. Is it showing an error for that sensor because a non-Volvo sensor was used? I was told that as well. My last mechanic said he had a Volvo scanner, and all three repairs he made just for check engine light problems involved a few sensors at least. If he installed the generic brand of sensors I purchased, would that cause error messages? And I was told he was probably the fuses or wiring. But who can check that? I just want straight answers and solutions; here's the problem, and here's what has to be done. Thanks. I'll keep looking for local mechanics that can do Volvo work.

 

What year and model, exactly what codes are present?

 

You can go to an Autozone or similar and "rent" (actually borrow) an OBD2 code reader or buy a $29 unit at Harbor Freight that will work just fine with an s40. There's a connector port under the driver's side of the dash - simply plug the reader in, turn the key to position 2 and follow the prompts. For the 2004-2012s the O2 sensor heater fuse is #33 in the engine compartment box on the drivers side.

Also where are you located? Dealers being expensive is really a relative term - most do charge a $20 an hour premium, have all the propietary tools/guidance/experience to do the job right and will install genuine Volvo parts which for the most part are more expensive but guaranteed to be correct for your car, plus dealers do a more complete review of the car with each service (so in short you pay more but get more). If you are ok with getting less/paying less and using after market parts, look for an independent shop that specializes in Euro cars. There's not much difference between Volvo and say a VW. They both use Bosch components, their systems are similar designs - about the only thing the indy's may not have is Volvo or VW's proprietary software tools (ie VIDA-DICE or VAG) but for your issue, their scan tools (which are way more featured than your $29 OBD2 reader) will give them all the info they need to resolve the issue. I use both a local indy and the dealer based on the issue at hand.