How to replace the crank sensor?

Question edited for clarity. Please ALWAYS include FULL 'year make model'.

The sunroof motor is small and in the head liner. There is often a mechanical way to close them if the motor fails. Refer to the Owner's Manual. It normally involves removing a pop-off cover and turning with a screwdriver or a crank handle is provided.

https://www.google.com/search?q=2001+Vauxhall+Astra.+replace+sunroof+motor

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https://www.youtube.com/watch?v=5WHBskK_F3o

Jerking or cutting fuel supply? How did you determine that? This is most likely a sensor in the engine. Could be a fuel pump relay but it most likely is a crank shaft sensor.

Fix your car right away, by clicking the link
2001 OPEL ASTRA SERVICE REPAIR MANUAL

locate the crank sensor there should be two screws and a electric plug pretty simple if u can locate the sensor

Crank Angle Sensor (CAS) should be replace.

Most battery last 48 months,check the date code on top of the battery to see how long it is in service.

take it back to the mechanic; the reluctor is not secured and, is slipping

The usual opel fault ,its the computer misreading the crank sensor owing to build up of magnetic flux in the crankshaft .Now what you do here is simple and if you dont it will cost an arm and a leg to repair.Now look on the front pulley and see if you have the earlier pulley still fitted as old stock on the assembly line ,Now look and see if it has a toothed ring and a support bracket top left hand side,now if it has the obtain a sensor for the earlier model and fit it to the front support ,now the two wires that go to the original crank sensor at the back right hand side of the engine disconnect the multiplug and then snip it off ,extend the two wires to accomodate the sensor you have fitted to the front pulley and try start it and if its still the same reverse the wires ,this will cure it i promise ,now for computer thats bolted to the inlet manifold right side then disconnect the mountings and move it away from the engine as far as the loom allows then tie it up with a couple of plastic ties so its away from the engine ,now mount a old computer fan to the casing of the module and wire it in to the ignition circuit via the fuse box ,leave that sill engine cover off the engine as well as this causes no end of problems here in spain with the heat build up and no air flow when driving.This will cure your problem i promise as i do about at least one a month of this type of engine like the astra and the 7 seater whatevers its called ,iam old and my memory ? .Now dont forget the polarity on the engine crank sensor if after fitting the new one and its still the same reverse the wires .

Any codes logged?? Had a corsa do this it was the lambda sensor (pre-cat) replaced with a non genuine part & fault returned 3wks later. Used a gm genuine part & fixed the prob. If you have auto data you can test sensor using ohms on a multi meter

opel astra ,which is marketed as vauxhall or holden ,also dawoo .right now what i need to know is and as a woman you have ommited to state, is it a manual or a automatic gearbox ,now remember the time zone difference iam in spain and you in vegamite land .Where my son is and i want to visit .