This is my first post, so pardon if I missed previous coverage of this topic. I bought a 1989 240 DL wagon in September 2006. So far, pretty good. My inspection is due February 2007, so I am hoping to pass - my county of residence requires emissions testing.

Recently, the 240 caught a case of the shakes - when idling the car would shake. My local Volvo mechanic (today) replaced fuel injector #1 and intake manifold gasket #4. Prior to this service, codes read 1-2-1 MAF signal fault and 2-1-2 Oxygen sensor fault. After service, the shaking subsided and engine performance appears to be great.

After driving the 240 for about 30 minutes, I sat at idle for 5 minutes and the check engine light appeared. I read the codes and now they say 2-2-1 which is the heated oxygen sensor. After reading through my Haynes Repair Manual, I realize I do not have some of the tools (ohmmeter) to test the O2 sensor. Haynes recommends replacing the O2 sensor every 30-50,000 miles.

Question - Should I proceed with replacing the O2 sensor? My only thought is that if the O2 sensor is good, then I could have an electrical problem. I am concerned that I will fail the emissions test if the O2 sensor is not working correctly.

 

Wiring is NOT a common problem.
Do you have a Volto meter?

 

tech - I am getting an ohm meter/ volto meter this weekend for free - a family member has a nice one that they are handing down to me. I plan on testing the O2 sensor voltage per the steps in my Haynes Repair Manual. Any guidance you can provide will be greatly appreciated.

 

It is easy connect the positive lead to the single wire and the negative to a ground and let the car run and watch the voltage.

 

I hooked up the multimeter today and got no voltage from the O2 sensor. I have ordered a new sensor and plan to install soon. Also will install new spark plugs - the distributor cap looks good and the spark plug wires are new(er) looking, so will defer replacing those. At this point, just trying to keep the 240 running. There are other items that need attention like suspension, electrical system and body work. Just have to make what repairs I can on a limited budget.

 

Do you have any voltage at the wire with the sensor disconnected?

 

No voltage there tech. I replaced the oxygen sensor yesterday. Also put in new spark plugs, as the old ones worn pretty worn. Thanks for your advice - I will be posting more questions soon.

 

Did you get Voltage with the new sensor?

 

Just checked and there is no voltage - guess I should have checked upon installing the new sensor. Any thoughts on why I do not get a voltage reading with the new sensor?

 

Try unplugging the engine computer and letting it sit for a few then reconnect and see if it is better.

 

Still no voltage reading

 

Hmmm I will have to see if i can figure out something tomorrow.