Transponder/ECU Problems-Or is it?

[KipVR 1]

My VR was running fine, then I parked it for five minutes, came back to it and it would turn over but wouldn't start. I left it for five more minutes and then it started no problems. I then drove it home a couple of miles, it cut out on me twice but started again no problems. Next day it started but after 50 metres it cut out on me. Eventually it would only start for a second and then cut out. Took it to VAG who told me it was the transponder Control Unit and Reader Coil. I told them this was unlikely as it did sometimes run for a while before it cuts out, not always just a second- like it does with the wrong chip in the key. They have replaced both (320 squid) and the problem persists.

 

They now tell me that the problem is an intermittent problem with the ECU and that they can't get hold of the ECU's any more so I'll have to find a second hand one, which they can't fit as it's used- ie they are telling me thay don't want any more to do with the car! Problem is, who can progam a new ECU if the ECU is at fault- do I have to transport it to the next nearest VAG stealership? Before I get the car back they are telling me I have to pay them for the work carried out that hasn't fixed the car in any shape or form!! Does anyone have any ideas what tthe problem might be? Suggestions? When it cuts out its a fast cut off-like I've turned the key off, no splutters or anything.. But the ignition remains on! Please help I'm going spare!!!

[Kevin Bacon 5]

Without checking with VAG-COM, that sounds very much like a dying crank sensor, especially as they've replaced all 3 components of the immobiliser.

 

I've never heard of a tranny box going. The coil and key do sometimes give up.

 

You need a CP ECU if that's what it is and you don't need to program it. The tranny box just sends a pulse to the ECU and that's it.

 

Try Steven's VW breakers 01245 362020 or Just VW/Audi 01728 660530, they might have an ECU. It's a Corrado OBD1, part no ends CP.

[KipVR 1]

Ah so the ecu doesn't have to have to be coded with the transponder CU? The reason VAG are telling me I have to pay up is because apparently they could not find fault with the ECU until the T CU was replaced, smells bad to me! Any way thanks for your advice, I'll ask them to check it. How easy is it to replace the crank sensor? Nice C by the way, looks identical to mine, only different colour.

[RW1 0]

ECU - Transponder & key.

 

Yes they do have to be coded for your car P.

 

Only one way now is the dealers with 7 didgit code & date & dealer code & country code via their GEKO system. Techie won't see what gets programmed. If you have the 4 digit code from a few years back, thats differnt, VAG-COM can do it.

 

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[dr_mat 0]

It does sound like a crank sensor to me, too..

Thing is, it's very difficult to find a crank sensor fault, and they might be saying it's the ECU just because they can't say for sure it's anything else..

Take the car to an automotive electrician and ask him to check the output from the crank sensor. It's pretty obvious if it's fecked. (They tend to lose resolution when they get hot ... and then can work fine after the block cools down a bit..)

[Kevin Bacon 5]

I stand corrected on the ECU coding then. The way I understood it, and is certainly the case with my OBD2 ECU, the decoder (transponder box) sends a pulse to the ECU to confirm you're good to go, assuming the key and the chip in the decoder match. I can't see the point of having a decoder in the ECU as well as the decoder box.

[RW1 0]

I was doing some homework tonight so the grey cells are still active :)

 

The system is hand shaking. The transponder immobiliser looks at the key, tells the ECU to go. Also both ECU & transponder box handshake digitally, not a pulse unless you mean a burst of comms. Once the engine ECU/ T Box OK it. they go to sleep until the engine stops.

 

Initially the engine fires as the hand shake takes longer and that would be unacceptable to crank the engine a few of seconds so it's the inverse, start and shut down if failure occurrs which is why the Corrado starts, revs for 0.5 second and dies when it all generates failed starting handshake.

 

Decoder is in the ECU as well other wise the car can be hot started as they once tried with mine ("CP" ECU). None "CP" don't need a key in the steering column (chipped or not) to be started.

 

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[joebloggsVR69 0]

They have replaced both (320 squid) and the problem persists.

 

£320!!!?!?!?! WTF?

I had similar problems, and got the keys recoded for about £52, and then after I still had problems, bought the transponder coil (£30ish).

 

Now starts fine :)

[Supercharged 2]

Yep, sounds a bit on the expensive side!!!!

[RW1 0]

Naa, a little bit maybe but it's a few quid only....... £50 at most for knocking off an hour. Underdash out, get at the box, refit new box, same in steering column for the sender, recode th ekeys, put all trim back = 2 hours. Add one hour cos "haven't seen a Corrado in years - ermmm". Good estimate really.

 

P. is talking about the keys recoded + sensor + the box inside the dash. Parts in total are £130. Plus labour for 3 hours at £50/hr for fitting and key recoding then + VAT = £320. Is correct ball court to expect.

 

The Coil is £35 but it's the box of tricks that costs another £100.

 

Anyways, don't think it's this. dr_mat is most likely but cos of the cost, just worth changing the ECU relay "109" in case it is playing up.

 

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[dr_mat 0]

(We had a pug main dealer write off the ECU on the missus' 206 once. They offered to replace it at a bargain price of only £800+VAT. Dealers are very quick to claim it's the ECU...

Turned out the transponder reader coil was dodgy, so the ECU wasn't unlocking. £35 fix. They assumed that since they couldn't get any diags off the ECU it must be faulty...

The same guy who diagnosed this for us now works on my VR when weird stuff is happening. He knows his auto electrics!

I spoke to him about my crank sensor^w^wunichip probs just recently, which is why I am so wise in the ways of failing crank sensors ...)

[Niges16V 0]

How weird! Came in early to work this morning to post a 'I need help' thread and you guys had already started it last night!!

 

Had an intermittant starting problem on my 95M VR6 and last night I was stuck at the fuel pumps for 20 mins until it got started. Basically the engine turns over but doesn't fire, and I also notice that the relay panel doesn't click. I have in the past waggled the wires & relays abit and then it started, but not last night.

 

I thought it was a loose connection to the transponder box under the dash as the guy who fitted my new CAT1 system a couple of months back mentioned that it caught him out a couple of times as the loom to it was a bit tight, but I can't find what he meant.

 

Where should I start, 109 relay or take it to a VAG dealer with a new credit card??

 

I sometimes wish I had stuck to my 2l 16V, so much simpler!!

[RW1 0]

The fact the car engine is not starting at all, even for 0.5 second means it's most likely not the key immobiliser.

 

It may still be a bad connection for the alarm immobilisation. Depends how the alarm has been used to isolate the car circuits.

 

Too tight, he would be meaning behind the fuse/relay panel. It's all a very tight bundle directly behind their and a rats nest of tricks.

 

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[KipVR 1]

Right, I've just got a sh crank sensor and relay 109, so tomorrow I'm going to plug them in and see what happens. Just to make it clear, it does sometimes start for longer than half a second, it will go for a few minutes before shutting down, I'm wondering if it is the fuel relay too, does anyone know which number one this is?

 

thanks for all your help guys, missing driving it already

 

Chris

[RW1 0]

P.

 

Only 3 days but it was off the road most of October with problems. Did get out in it last Saturday.

 

Fuel Pump relay is the one on the bottom row next to the door marked 167. Part number 191 906 383C

 

C.

[jpowell79 0]

Right, I've just got a sh crank sensor and relay 109, so tomorrow I'm going to plug them in and see what happens. Just to make it clear, it does sometimes start for longer than half a second, it will go for a few minutes before shutting down, I'm wondering if it is the fuel relay too, does anyone know which number one this is?

 

thanks for all your help guys, missing driving it already

 

Chris

 

I've got the same issue, and just ordered a ECU relay and fuel pump relay...... did this fix it or was it the crank sensor?

[Kevin Bacon 5]

A 7 year thread resurrection has to be a record on here? :D

[KipVR 1]

Yeah right that is one dormant thread dug up! But to answer the question, I think it was the connection from the coil reader to the box playing up :-)