P0130 code after changing ABS unit

[edsimmo]

I have a 1999 S70 with a non-turbo engine. It has about 160,000 miles on it.

After months of dealing with the ABS light and Check Engine light going on and off intermittently, I sent my ABS unit to Victor Rocha. He repaired it and turned it around in the same day. I had it reinstalled exactly a week after I took it off, all for a cost of $165 ($140 to Victor and $25 to ship it to him 2nd day air) - very nice. As he predicted in his excellent documentation, the ABS light went off when I reached a speed of 15mph but the Check Engine light stayed on. I read the following codes - P1081, P0130, P0600 and P1054 - then erased them.

The Check Engine light stayed off for about two days, then came back on. I read the codes again - just P0130 this time - and erased it. Unfortunately the Check Engine light is now on again (after about 2 days), and I'm sure it's the P0130 code. I understand this indicates a problem with Bank 1, Sensor 1, which apparently is the front O2 sensor.

Question: is there anything I could have done in uninstalling and reinstalling the ABS unit that could possibly be giving me the P0130 error? I carefully unattached and reattached the hoses leading into the box containing the air filter, but could an issue with one of those hoses be causing this error? It's just odd that my Check Engine light went on and off with the ABS light, but never stayed lit all the time until after I did my ABS repairs.

At some point in time in the past - I don't remember when - the O2 sensors were replaced by my friendly Volvo dealer at what I remember to be a significant cost. It was probably at least 60,000 miles ago. Might it just be time to replace them again? And don't worry - I'll be doing it on my own this time, or at least ordering the parts and letting my neighborhood mechanic replace them.

Thanks in advance for your input and insight.

[jblackburn]

That's for a missing/faulty signal from the front O2 sensor.

While it has absolutely nothing to do with the module itself, the wiring for the O2 sensors is just behind the transmission there below the ABS module - perhaps you just need to have a look over it all, and remove and clean both of the connector terminals. The little red thingy slides out of the black plastic part to remove the plug (at least on a '98 model).

[edsimmo]

Thanks for the info - I will check that out this weekend.

Also meant to post that I'm not dealing with any obvious engine issues after getting the P0130 code - car is starting fine with no rough idle, and I'm still getting around 27mph on the highway.