Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: countrywoman on 19 October 2025, 10:20:23
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Did a scan and fault code 31 (no speed signal) came up, it should show cranking speed on lie data so looks like the sensor has gone down. Drove fine on the way home but no go next morning. 97, 3L v6 so what is part number and where is best place to get a Bosch one?
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That code is perfectly normal if the car isn't running. 19 is the more usual for a crank sensor failure.
You should see the RPM on live data.
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Should it show if I crank it on live data, I would have thought so.
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Should it show if I crank it on live data, I would have thought so.
You should see the RPM signal on the Motronic ECU during cranking - this is derived from the crank sensor. Actual crank signal might be too fast to see with any diags tools I've seen, but you will see it on a scope if you have one.
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Assuming you actually have a failed crank sensor then the best way to be sure about which part is required is to pull it and have a look. There are three sensor variants, one with a rectangular sided plug and two with oval sided plugs, on the sensor tails. All three sensors may fit the engine however they have differing electrical resistance.
As your engine is a 1997 V6 then the sensor required is probably, but not certainly, Bosch 0261210131 aka GM# 90540743/Opel Kat 12-38-740. The Vauxhall/Opel EPC can't be trusted for these sensors. However the sensor will usually have a Bosch logo and the Bosch part number embossed. Some will also have the GM part number stencilled on. Just make sure wherever it comes from that it's a Bosch part with the Bosch number on it.
This sensor also has an associated "Production" part number, lots of Opel parts do. This is 90494182, which is also used as the spare part number for Cadillac Catera and Saab V6. 90494182 is not a supersession, it's still the same Bosch 0261210131 and the part in the package will say 90540743, if you can find one.
The sensor, if indeed it's still being manufactured, won't be made in Germany. I seem to recall they're from Slovenia or maybe Romania. And it's this sensor you will get if you can place a special order through a Vauxhall dealer.
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Having a look at it today, I assume that the fuel pump gets a feed when you crank engine over like most systems and does not need a speed signal to do this??
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Managed to get help cranking the engine, yup feed to pump so fitted the new pattern one I had and she fired up!! So was a faulty fuel pump.
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Nice to get a result!