Dear Fellow Brickboarders,

Good p.m. and may this find you well. This post concerns a non-turbo 93 940 wagon (103K), with Rex/Regina fuel injection.

Mileage recently deteriorated (over three week-period) from 20-21 to 17. Had major workover done 1+K ago. I use Shell Regular (87) gasoline and have used a fuel system cleaner since I got the car (101,250K). I do not know what fuel the previous owner (PO) used, but could find out, if that's relevant.

Fuel pressure regulator replaced by P.O.'s Volvo dealer at 34,682 miles, end-Dec 95. (This is why I like having PO's records).

The injectors were last cleaned by PO's non-Volvo mechanic at 93,315 miles, end-Aug 01.

There is no record of of a fuel pump change. I believe R/R systems have only one, in-tank pump.

OBD Codes = 132 and 231.

132 suggests battery is low/high (not obvious what to do about this).

231 = Self-adjusting Oxygen Sensor is not working.

Is this as simple as it sounds, i.e., do I simply need to replace the oxygen sensor? I presume this sensor screws into the exhaust pipe, just before the cat converter.

If I going in the wrong direction, please set me right.


Thanks for your guidance. I am much obliged.

Yours faithfully,

spook