Dear Chris Mullet,

Hope you're well. According to the Volvo pocket data booklet - Cars (700, 850, 900) 1991-1996, OBD Code (from Port A1 [Transmission]) 3-1-1 = Engine Speed Signal from Gearbox Absent. This code is applicable to vehicles with AW30-43 and 50-42 transmissions.

This sensor is Volvo #3514651. It is available from https://www.fcpeuro.com/Parts/?keywords=3515641 . The cost is just under US$100.

Based on the picture shown on the www.fcpeuro.com website, this under-body-mounted sensor's two wires are exposed to the elements. While there's a protective plastic sleeve, the wires themselves are exposed where they enter the wiring harness connector and the sensor's body, rather than surrounded by molded-on plastic sheathing. Thus, it would not surprise me if the wires have failed.

According to the parts diagram shown in Volvo VADIS - a superseded dealer parts/service database - this sensor is mounted on the driver's side of the transmission, about mid-way up, just to the rear of the bell-housing.

Hope this helps.

Yours faithfully,

Spook