3-1-1 code, RPM sensor, 850

1993 850 2.5 20v GLT....Autobox replaced by Volvo after about 18 months has
been fine since

I've got a flashing 'up' arrow on my dash (managed to reassure the wife that
she was not about to be ejected through the sun roof)
The car drives fine, if it wasn't for the flashing arrow I would be none the
wiser that there was a fault
The fault code showed 3-1-1, RPM transmission sensor.
I can cancel the fault code, but fault come back as soon as the car reaches
about 15 MPH (before the ABS cuts in)
The guys at Volvo were not very forthcoming as what the problem might be
To replace the sensor is about £55, if I do the work.

My questions are

I did have the radiator fail and mix the auto box fluid with the coolant.
This I have fixed and have done my best to flush both systems. But I noticed
that the transmission fluid is still looking emulsified, could the water
content be effecting the sensor?

Do these sensors 'play up' ? I dont want to spend £55 to find the fault is
elsewhere

Also where the hell is this sensor? the Guys at Volvo were at a loss (or did
not want to say)

As I said the car drives fine!!

Thanks to all for any advice and help........ttfn......Alistair

 

Probably a bad connection. The sensor is located (I think) just behind
where the cable harness connects to the transmission. This is easily
visible when the air filter box is removed.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
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