Hi Art. You're suggesting the OP's original sensor may be okay when seeing the 180 ohms through the sensor coil (pins 1-2)? The OP of course needs to check the integrity of the foil shield on pin 3 to chassis ground, both visually and electrically.

My understanding, and I'm sure you'll correct me if I'm off base here, is that the waveform of the CPS signal is very sensitive to interference. The spiral wrap aluminum foil is the shield and needs to be grounded at both ends to the chassis, otherwise the open segments not only permit intereference at the damaged location, they become antennas (okay, antennae) creating interference all along the cable that more easily disrupts the purity of the waveform. The foil commonly fails at the flex point where the cable goes into the sensor, part way up scuffing against things like dispstick tubes and cooling system plumbing, or at any sharp bends in the cable routing. This is often evidenced by damage to the insulation, but not always. The foil doesn't have to be damaged all the way around to become a problem as it's a spiral.

FYI to others, there are two standoffs (plastic clips), attached to things like the dipstic tubes and waterpump return line, used to minimize cable flexing and bending from the engine rocking around, but these often break or go missing. I make my own standoffs out of quality large black zip ties looped through a segment of vinyl tubing that usually last a couple of years. In damaged areas, some people report success baring back a little bit of insulation and wrapping with aluminum foil to restore the shield, but at that stage I always opt for a new sensor.

When the sensors fail they often start misbehaving before there's a no start. Questions to you Art, when the sensor coils fail, do they just tend to get weaker, or do they tend to become increasingly intermittent, like under temparature change? In my experience the OBD system does not necessarily report a missing signal, and when it does it's often the code for a missing signal being passed from ignition controller to the fuel ECU (1-3-1 on socket 2) suggestig a weak signal, rather than from the sensor to the ignition controller (2-1-4 on socket 6) suggesting a failed sensor coil or broken wire. That suggests to me that a failed shield would be the issue in those cases. Also in my experience, failing sensors seem to first start misbehaving at a warm start. Comments?

Genuine Volvo sensors will of course be the most reliable, but aren't overly cheap. A variety of aftermarket sensors are available for considerably less and I've always had good luck with the ones sold by the more reputable parts houses. There are ones being sold out of China for as little as $5-$10 with free shipping, but I have no intention of wasting even that little amount to see if they're any good or would last more than 5 minutes.

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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now