HELP - URS4 Not Starting...no spark...immobilzer??

[lcsmith]

I will post the ECU number when I get it back from the "specialists" as being the pillock I am I didn't take a note of it before I sent it away

I am going to have a closer look at the wires related to this immob to see if there are any that look suspect and also to take a note of where they go and what colour they are.........but my electrics skills are limited to say the least so I fear this may have to be sorted by a garage............which means less beer tokens ...
....but on the plus side I can get my car back on the road fingers crossed..

[twoqu]

I guess the trouble might be if they have snipped original wires to connect the immo unit in series. Obviously then you might be left with some unconnected wires which will put you back in the same position!
To be fair ecu's seem to be pretty robust considering the abuse tey have to put up with in an automotive application!

[lcsmith]

Are immobs not always wired in series? That way you can't just snip wires and drive off with the car, if you want to get rid you have to join up all the original wires which isn't a 5 minutes job at the side of road......bad news for would-be car thieves...

Robust or not I don't think any of it will be in a very good state after I throw it all over the cliff......which is what it deserves, but I do feel I'm getting somewhere now....hopefully

[lcsmith]

Just recieved my ECU back from Blue Streak.

The part numbers off my ECU are;
Bosch No - 0 261 200 465
Audi No - 4A0 907 551 AA


You guys were saying that it was impossible for the immobiliser to immobilise the ECU, so I'm beginning to wonder whether the ECU is knackered or not....? The technician I spoke to didn't seem to be that positively sure with an of his answers to my questions....

[twoqu]

Well thats an early one without immo. Without trying to confuse you further I was just trying to point out that the early ecu is dumb. If you put the power supply, both 12V battery and ign and its earthed then it should work assuming all the sensors are functioning. Of course its possible for the aftermarket immo to immo the ecu but it does not stay immoed after removal from the vehicle. The later ecu which is a 551C is immo equiped. Hard to explain but the factory system uses a transponder in the key, a reader coil in the ign barrel, a seperate immo box of tricks and lastly a compatible ecu. I am not 100% sure but I think I read somewhere that the immo unit sends a pulsed signal into the ecu.
It would be possible to switch your ecu into any other S4/S6 and it should still work. You cannot swap an immo ecu 551C/E into an unimmo vehicle as the car will start briefly then cut out.
So back to the non standard immo as the potential problem as clearly it can only immo the car by interupting a vital signal. Just be methodical and trace the wires!

[lcsmith]

Well by going on what you've said the ECU should have worked when tested by Blue Streak, and couldn't have possibly been immobilised, therefore having failed it must be knackered......am I missing something?

Well thats an early one without immo. Without trying to confuse you further I was just trying to point out that the early ecu is dumb. If you put the power supply, both 12V battery and ign and its earthed then it should work assuming all the sensors are functioning. Of course its possible for the aftermarket immo to immo the ecu but it does not stay immoed after removal from the vehicle.

[twoqu]

Correct! If you are confident of their abilities!
So there is always the possibility that the ecu has a intermitant fault but I can't see how the ecu can be immobolized. I guess it might be possible on the later ones as there must be some additional circuitary in addition to the known software. Perhaps Paul N might have noticed something!
Can you not swop your ecu into your mates for a weekend? If it works then we are back to the immo. As long as he keeps his original with him so he is not caught out. It might assist your diagnosis. Starts to get expensive changing stuff for nothing!

[lcsmith]

His car is an L reg Audi URS4, without factory immob so it will have the same ECU. I had thought about swapping his one over, but his car has a really horrible scorpion immob / alarm and I didn't want to turn his car into a non-runner like mine, and as well as the fact I didn't know that the ECU could be swapped without re-coding, etc.

Would swapping the ECU across affect his Immob / alarm?....I suppose it depends how its wired in......?
Is it no problem to do this, swapping ECU's back and forth...generally?


I have been V-lucky with tips / tests from this forum to rule things out rather than buying new, I've only actually renewed the cam position sensor which was actually broken anyway, but your right its bad enough having to pay for new bits for these Audi's when you need the bits, but it would be really painfull having to do it when its not needed!!

[twoqu]

Well if nothing else its a good test of friendship!
Seriously though, As we have established that aftermarket immos are external to the ecu there shouldn't be any problems. If the vehicle were factory immo then I think you would need to re sync them to the immo with vag com.
If you swop your suspect one into his then its unlikely to do any damage whereas if you put his undamaged one into yours and it gets fukked up then red faces all round.
The ecu will take a while to adapt but I can't see any other problems. If it works fine then thats another thing eliminated.

[S2central.net]

Twoqu is right - your ECU is NON immo... Swap it any other ABY or AAN to see what gives.

Your man from BlueStreak is a **** and a liar.

If the ECU works in another car then it MUST be your aftermarket alarm/immo... Tell me how that is wired privately.

[lcsmith]

Ok update guys...........last night I got a shot of my pals S4 to swap the last suspect bits over.
First I swapped over his Power Output Stages into my car no difference, then
I put my ECU into his car and it ran fine........so basically it looks like it must be the IMMOB......or I suppose a broken wire.....?

Summary of things Checked and Ruled Out;
All Fuses / Relays,
ECU,
POS's,
Earths,
Coil Packs,
Spark Plugs,
Both G4 and G28 sensors,
G40 sensor,
Engine Timing,
I have fuel.

I'm going to book it in to the Electrical Engineer to get the IMMOB and all related sh*te removed..........I'm really bad with electrics

So one step closer, anyway cheers for now!

[lcsmith]

Just one thing that crossed my mind is..........where is the fuel pump relay?..........the reason I ask is that I was thinking that maybe the fuel pump relay also had something to do with the spark..........you know like maybe half the relay works the fuel half works the spark........? just a thought.......

Also I've gone and closed the bonnet without hooking up the cable to the cross-member, so now the bonnet stuck shut........can you open it through the grill with a hook?.......or maybe from underneath in a pit?.........this happened to any of you?

[quattro20v]

I think it's this one under the steering wheel.


And yes that happened to me too, i opened the bonnet underneath with some 80cm pipe.

[S2central.net]

I'd have to look up AAN schematics... The fuel pump relay is an a different location to the S2/RS2.
But it is only triggered by the ECU, when its happy the engine is rotating fast enough, to activate the fuel pump. Easy to test of course.

I hate faults like this - I could solve them in half a day MAX if I had hands on...

[lcsmith]

Ok the guys at the garage tell me that there is NO pulse from the plug at the injectors.....any ideas?

The second thing is does anyone have wiring diagrams for the URS4 or at least for the ECU?

Third thing, is this a motronic, KE-motronic, etc?