Hi, all,

Check engine light came on this afternoon. I was told it was on a couple of weeks ago(when I was way). I will give it a couple of days to see whether this one will go away. It seems there was no performance drop.

Could weather changes trigger this? Any suggestions on where I should start looking?

Thanks,
Paul

Placed an order with Don this morning and expect to receive it on Monday. Any special tool(s) and/or materials should I prepare for the job? What is the torque spec for the front O2 sensor?

Thanks very much.

There is probably a torque spec for every nut and bolt, but because you are not trying to hole 2 pieces of metal together, snug should be OK. About 15-20lb.

You won't be able to use a socket, so I hope you have nice wrenches. Soak the non-existant gap between the O2 sensor bolt and the pipe with PBBlaster or some other good penetrating oil. WD40 is not a penetrating oil! I would put some PBBlaster on it every night until you are ready to take it off.

Before you do anything, compare the plug from the new one to the old one. They need to be the same!

An old trick is to clip off the wire on the old one, thread it through the box end of the wrench, and apply liberal pressure to the wrench. Don't let the wrench slip with out numerous band aids laying about :)

Put the new one on with the open side of the wrench. You can oil the threads if you want, just don't get oil or finger prints on the business end of the sensor.

Klaus
--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

Thanks a lot, Klaus.

I am going to get a can of PBBlaster tomorrow and apply it deligently. I could imagine from your description of how tough it will be to remove the old sensor. I will try my best.

Would it be helpful to heat it (with a torch) before removal?

The normal operating temp for a converter is about 500F. Unless someone else chimes in, I wouldn't bother heating the old plug.

Klaus
--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

I guess the old trick from doing plumbing job does not apply here.

I just cleared up the CEL by disconnecting car battery for 15 minutes. I have not driven the car yet; but CEL was off when the engine was running.

Thanks, Klaus

Once the car is driven for a while, it will come back. Disconnecting the battery does more than just clear the codes, it also clears the computer of its learned driving habits. Once that info is stored and the same DTC is recorded the second time, the CEL will light up.

A lot of people do this when selling a car, the light will stay off for about a week. And then the new owner is stuck with the bill.

Klaus
--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

The CEL came right back this morning so I don't have enough time to sell my car. :-)

The O2 sensor is on its way. Will get it replaced this coming week.

Have a great day.

Hello, Regarding the computer relearning your driving habits: When you clear a code(s) the absence of those driving cycles will prevent your car from passing state inspection. I thought I was being so clever. Kira

Thanks. I learned that last year after the battery was replaced. The guy had a hard time to perform the state inspection. I had to wait one more week to let the car computer recording some driving data.

Got the code scanned at Autozone and only code shown was P0135. The guy reset the code for me; but it came back on in less than a minute after driving. My understanding is the code is front O2 sensor related. I am going to check any problem with fuse. If nothing wrong with it, I am due for a new front O2 sensor, right?

Car seemed losing some power especially at higher rev. There may be mileage drop; but not crazy (a couple of miles per gallon).

Anything else should I also look for?

Thanks,

Low voltage wires that go to the ECU are not fused. Your P0135 = O2 Sensor Heater Circuit Malfunction, front O2 sensor.
Either the wiring went bad, which I doubt, or you are in need of a new O2 sensor. Start shopping.

Klaus

--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

Thanks, Klaus.

I guess that's what I have to do next - get a new O2 sensor. One question. Which brand of sensor should I purchase - the Denso one from FCPgroton or Bosch from somewhere else?

Thank you very much.

Paul

Bosh and only Bosh. Stay with OEM if you can afford it.

Klaus
--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

Klaus,

Just got the O2 sensor (Genuine volvo). The manufacturer is actually Denso from Japan, not Bosch. My V70 is a non-turbo base model.

??

Best,
Paul

thanks a lot. Surely go for Bosch

Just checked the manual; but didn't see there's a fuse for O2 sensor??

Any suggestion?

Thanks,

Thanks you all for your inputs. Have not got a chance to buy a scanner or get a code scanned since I have been busy from my job.

A little update. The CEL was still on this morning on my way to work. Question: The car has about 99k miles. I don't remember I have done any cleaning job for many years. Should I do some cleaning first, say air intake, etc?

Have a good day.

Check your gas cap on the way to reading your codes.

Klaus
--
Proud owner of a 1967 220S. If I had more room, I would have more Volvos.

Drop by Advance or whatever auto parts store is close to you and they will read & clear your codes for free. It's better to not drive it with the light on, as the car runs rich. Post back here with your findings, and people will be able to give you more advice.

I had a MAP sensor that got grumpy when the weather would change dramatically about a year ago; I cleaned the contacts and accidentally hit it pretty hard with a wrench trying to fix something else; I'm not sure what fixed it. My Advance got to know me by name at that time & would just hand me the scanner when I walked in.

Hello, For you, and many others, it's time to buy a code reader. You don't need the fancy graphics offered by some models. Just make sure the one you buy is CAN compatable. Many which are on clearance sale are not. Anecdote: A half tank of cheap gas generated a P0442 code in my '99. That's the same "Evaporative emmisions system-small leak detected" code you'd get with a loose gas cap. There were advantages in being able to read my code on the spot. I bought a ScanGuage when they first came out. Today it's called ScanGuageII and costs more. I swore I would shop diligently for a "better" unit. I haven't had to. Kira