SCU help or information??

[st3f4n]

Hello there, an old memeber re-joining here.
After some advice...
Purchased off ebay last night a 54 plate facelift zr, with what is pressumed scu fault. Done a lot of reading on the site etc but nothing seems clear to answer my questions.

The car ignition does not come on, Apparently no lights no ignition etc etc
Obvs the car does not start
They have been told by a rover garage in plymoth the scu is at fault and it needs a new unit and reprogramming fobs, for which they have quoted £800.
Apparently the car just wouldnt start one day, no symptons (the abs light had been coming on itemitently before hand). this is basically all i know until i collect the car one day this week. Its had a brand new battery so its not that

Firstly do these sound like the symptoms of a locked scu?
What exactly is the scu, Immobisser system?

Iv got more questions but il hold back on asking untill these two are answered so i can try and understand myself a bit better

Regards
stefan

[r44712]

Originally Posted by st3f4n

Firstly do these sound like the symptoms of a locked scu?
What exactly is the scu, Immobisser system?

Not so much "locked" more like knackered...

The SCU is the Security Control Unit which on later models was combined the Body Control Unit (BCU). The BCU controls just about everything electrical. The SCU dealing with the electrical aspects of the security system.

Earlier cars had a separate BCU and SCU and aguably were more reliable, but let's not get into politics. I've no issues with mine.

I think £800 is reasonable (no doubt someone will be along in a minute to say "oh no it isn't") given what they need to replace/reconfigure. Their remedial steps sound par-for-the-course for a B(S)CU repair job.

[r44712]

I don't know how technical/electrically-minded you are, but have a read of this.

I suspect that the immobiliser part of the system is broken - hence why unable to start the car.

[starlight14]

are the fuses okay in the engine fuse box one supplies the bcu electronics. check the igintion switch is operating the electrical switch. Do the hazard lights flash?

[st3f4n]

Originally Posted by r44712

Not so much "locked" more like knackered...

The SCU is the Security Control Unit which on later models was combined the Body Control Unit (BCU). The BCU controls just about everything electrical. The SCU dealing with the electrical aspects of the security system.

Earlier cars had a separate BCU and SCU and aguably were more reliable, but let's not get into politics. I've no issues with mine.

I think £800 is reasonable (no doubt someone will be along in a minute to say "oh no it isn't") given what they need to replace/reconfigure. Their remedial steps sound par-for-the-course for a B(S)CU repair job.

Thanks.. Been quoted £400 for a new SCU, all programmed up etc. seems a good price atm.

Is the BCU phsically connected to the SCU? Hence if you get a new SCU your actually getting a new BCU aswell?

Also iv had a read through that post by technozone. Tad complicated in some points for me but i get the basics... But my feelings were also the immobisser part was broken.

APPAERNTLY, no hazzards etc etc

[r44712]

Originally Posted by st3f4n

Is the BCU phsically connected to the SCU? Hence if you get a new SCU your actually getting a new BCU aswell?

The BCU and SCU are physically "in the same box", with older models (circa '04 reg) it used to be two seperate physcial boxes. So, yes you're replacing both functionalities with the one unit.

[starlight14]

The ABS coming on is likely to be voltage dropping below 10v. Check the heavy duty cables and crimps at the negative slam panel and the bolts across the 140amp fuse. there could be a short to the chassis. This does seem more like a less in electrical power from the engine fuse box area.

headlights should still work without the bcu running because they are independant.

[Southside]

Ignition not commin on atall doesn't sound like a BCU issue to me. Alot of people will automatically assume BCU as soon as any electrical problems are mentioned with a mk2 as it seams to be a common failure.

But surely ignition system is linked to the engine bay fusebox/ECU? I suspect a dodgy relay or earth. Or even the main posotive battery lead faulty/loose

[st3f4n]

Thanks for the advice, spoke to somebody who repairs them for a living, and he says it does sound like the symptoms of a ******ed scu. Not a great design by rover tho if it even stops the hazards etc.

Was going to have the bcu checked on the way back of collecting the car, but might bring it back and have have a look myself then let an auto electrician have a look.

Like I say still haven't seen the car, the owner doest seem to knowledgeable after speaking to them, but a rover dealership/garage has diagnosed the car. Although more than one person has told this isn't exactly reliable

Regards

[r44712]

Originally Posted by st3f4n

Thanks for the advice, spoke to somebody who repairs them for a living, and he says it does sound like the symptoms of a ******ed scu. Not a great design by rover tho if it even stops the hazards etc.

I'd go with the fubarred BSCU too - it's the backbone of the elctrical system.

[Lukas]

Originally Posted by st3f4n

They have been told by a rover garage in plymoth the scu is at fault and it needs a new unit and reprogramming fobs, for which they have quoted £800.

Originally Posted by r44712

I think £800 is reasonable (no doubt someone will be along in a minute to say "oh no it isn't") given what they need to replace/reconfigure. Their remedial steps sound par-for-the-course for a B(S)CU repair job.

I would shop around if I were you before agreeing to pay that .... I had a new SCU fitted & programmed last year by Best of British in Birmingham for about £400 (may have been even less, but Im not at home so cant check the receipt) and a quote from another rover garage in the region of 500/600

Where abouts in the country are you Stefan? Maybe someone knows of a good 'cheap' MG specialist near you.
p.s. welcome to the forum


Thanks,
Luke

[technozen]

The SCU is available direct from the manufacturer, Pektron, for £125.

The symptoms you describe do not sound like an immobilised SCU but if it is faulty I would expect water damage.

Have you removed the SCU to see what condition it is in?

[Plumster]

earlier this year, I had electrical problems where the car died and would do nothing ( no dash lights etc). After several hours trying to remove bcu ( I have a/c), in frustration I sprayed wd40 in the ignition barrel, within minutes everything was back to normal. The car went to an auto electrician to be sure but they found nothing wrong, and it hasnt put a foot wrong since.

[starlight14]

its possible that any of the multi way plugs has never been pushed home when the car was manufactured and has just come out slightly and not making conntact.

[st3f4n]

Originally Posted by r44712

I'd go with the fubarred BSCU too - it's the backbone of the elctrical system.

Originally Posted by Lukas

I would shop around if I were you before agreeing to pay that .... I had a new SCU fitted & programmed last year by Best of British in Birmingham for about £400 (may have been even less, but Im not at home so cant check the receipt) and a quote from another rover garage in the region of 500/600

Where abouts in the country are you Stefan? Maybe someone knows of a good 'cheap' MG specialist near you.
p.s. welcome to the forum


Thanks,
Luke

Thanks for the re-welcome luke, Iv got a quote for about £400 all in, this included putting a new unit in and checking i got power and then proceding to program it up etc... Also im from lincolnshire

Originally Posted by technozen

The SCU is available direct from the manufacturer, Pektron, for £125.

The symptoms you describe do not sound like an immobilised SCU but if it is faulty I would expect water damage.

Have you removed the SCU to see what condition it is in?

Havent even seen the car yet. So not removed or touched, just going off what the current owner has told me. If it turned ut to be this, and i brought a new unit who would be able to programme the SCU to the car and to the fobs etc??

Originally Posted by Plumster

earlier this year, I had electrical problems where the car died and would do nothing ( no dash lights etc). After several hours trying to remove bcu ( I have a/c), in frustration I sprayed wd40 in the ignition barrel, within minutes everything was back to normal. The car went to an auto electrician to be sure but they found nothing wrong, and it hasnt put a foot wrong since.

Il try this on collecting, you never know!

Been quoted about £60 by a local (good) auto-electrian to have the problem fully diagnossed. So i rekon this will be my first step when i get the car.

Keep the advice coming

Regards

[starlight14]

Originally Posted by st3f4n

Thanks for the re-welcome luke, Iv got a quote for about £400 all in, this included putting a new unit in and checking i got power and then proceding to program it up etc... Also im from lincolnshire



Havent even seen the car yet. So not removed or touched, just going off what the current owner has told me. If it turned ut to be this, and i brought a new unit who would be able to programme the SCU to the car and to the fobs etc??



Il try this on collecting, you never know!

Been quoted about £60 by a local (good) auto-electrian to have the problem fully diagnossed. So i rekon this will be my first step when i get the car.

Keep the advice coming

Regards

hope he is okay. as said every body jumps to the conclusion of the BCU and it is true if water has entered the unit. However, more things seem wrong from your first note. Simple checks are easy to do and may save £100 of pounds.

However, to most people car electrics are a mystery so they have no choice but to accept what a garage will say.

[st3f4n]

Thanks for all the replies, well after reading technozones post and speaking to someone it may not be the SCU... The car has no ignition power what so ever! no hazards, no lights, doesn't crank etc etc,

So what other points of call would you check after this??