Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: rossi123 on 14 January 2012, 18:15:23

Title: Po725 engine speed circuit malfunction
Post by: rossi123 on 14 January 2012, 18:15:23: Hello all got a new problem my car is coming up with po725 fault code not really sure what it is any guidance would be appreciated, the facts I have are there's no faults in the engine but when you go into the abs ecu there is a message saying 246-(4) no engine rpm present, I have looked on google and it points to a crank sensor however we have fitted a crank sensor recently and fault code 19 doesn't come up that's about as much info as I can give any help would be great cheers
Paul
Title: Re: Po725 engine speed circuit malfunction
Post by: SIR Philbutt on 14 January 2012, 21:53:09: Loose connection ? - wire breaking down ?

Just had similar on SWMBO scenic - wire o/c in loom to relay - took hours to find >:(

Just a suggestion ;)
Title: Re: Po725 engine speed circuit malfunction
Post by: Marks DTM Calib on 14 January 2012, 21:54:47: Have you cleared the codes and they keep coming back?
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 14 January 2012, 22:31:08: I'll have a look at wiring and yes I have cleared the codes and they do keep coming back I was wondering if it could be the dreaded abs ecu which I have had problems with before but not for ages I had it repaired so not sure ??
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 13:34:05: Right then new development the tc light comes on and the rev counter starts bouncing up and down but sometimes it doesn't work at all however this only happens when the engine is at normal temp when it happens it goes into limp mode, so we park the car up with fault on, for half hour, when we come back fault has gone. This one is a head scratcher any ideas welcome cheers Paul
Title: Re: Po725 engine speed circuit malfunction
Post by: Marks DTM Calib on 16 January 2012, 15:19:59: Smells of crank sensor, rpm signal has nothing to do with the ABS unit.

Give us a clue on the engine type. :y

I am guessing a 2.6 or 3.2 V6 petrol?
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 15:27:03: It's 3.0 ltr v6 facelift, I have recently put a crank sensor on so might be that then ??
Title: Re: Po725 engine speed circuit malfunction
Post by: Marks DTM Calib on 16 January 2012, 15:31:31: Quote from: rossi123 on 16 January 2012, 15:27:03
It's 3.0 ltr v6 facelift, I have recently put a crank sensor on so might be that then ??

Was it a genuine crank sensor or cheap pattern item (which are known to be problematic at times).

Guessing the fault code you listed is from the ABS unit or instruments?
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 15:50:09: Yeah it is from the abs and not sure I'll find out cheers mate
Title: Re: Po725 engine speed circuit malfunction
Post by: SIR Philbutt on 16 January 2012, 19:55:42: info on code - crank sensor - follow link

http://www.permoveo.ltd.uk/tabid/122/OBD-Error-Code/p0725/Diagnostics/Vauxhall/Default.aspx (http://www.permoveo.ltd.uk/tabid/122/OBD-Error-Code/p0725/Diagnostics/Vauxhall/Default.aspx)

I would start here and cure before anything else

Hope this helps

Phil
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 20:17:28: Cheers looking more and more like the crank sensor but I've talked to the bloke who put it on with me and where both pretty sure it's a genuine vauxhall part have to have a close look
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 20:21:59: If it is a communication fault how do I narrow that down cuz I'm a bit confused know as to what to do next ??
Paul
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 20:24:42: One last thing would the traction control light come on with this fault because it does come on with this fault occurs ??
Cheers Paul
Title: Re: Po725 engine speed circuit malfunction
Post by: Marks DTM Calib on 16 January 2012, 21:03:22: Yes, an input for the TC calculation is engine speed.

The fact its doing it when hot also hints at crank sensor.
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 16 January 2012, 21:22:14: Cheers I've got another elite but it's prefacelift but same engine I thinking of trying crank sensor to see if that sorts problem but then again, if it ain't broke don't fix it. Think I'll just bite the bullet and buy a new crank sensor.
Paul
Title: Re: Po725 engine speed circuit malfunction
Post by: rossi123 on 29 January 2012, 10:24:50: right then think i've sorted problem fingers crossed we routed the crank a different way actually the same way as our other omega and that seems to have done the trick so far 8)