# My TT wont start, need help (Solved)



## Black_64 (Oct 31, 2005)

Hi,

Today my TT want start. The motor is turning but it does not run.
Sometimes it starts but when you shut off the the next time it wont start.

There are no symbols displayed, all looks normal.
Fuel pump get's no power (voltage).

I cant read the error's with vagcom (worked before).
Say's no connection.

When the engine will run i can see on the display. The only difference is that the lite EPC is on.
When it is i now the engine will run.

When i see the EPC lite then i can read the error's with vagcom.

This i get (did first a reset by disconnecting the batt.):
15 Faults Found:
17522 - Oxygen (Lambda) Sensor: B1 S2: Internal Resistance too High
P1114 - 35-10 - - - Intermittent
16989 - Internal Control Module: ROM Error
P0605 - 35-00 - -
17521 - Oxygen (Lambda) Sensor: B1 S1: Internal Resistance too High
P1113 - 35-10 - - - Intermittent
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
17633 - Fuel Injector for Cylinder 1 (N30): Short to Ground
P1225 - 35-10 - - - Intermittent
17635 - Fuel Injector for Cylinder 3 (N32): Short to Ground
P1227 - 35-10 - - - Intermittent
17636 - Fuel Injector for Cylinder 4 (N33): Short to Ground
P1228 - 35-10 - - - Intermittent
17634 - Fuel Injector for Cylinder 2 (N31): Short to Ground
P1226 - 35-10 - - - Intermittent
17833 - EVAP Purge Valve (N80): Short to Ground
P1425 - 35-10 - - - Intermittent
17955 - Boost Pressure Regulation Valve (N75): Short to Ground
P1547 - 35-10 - - - Intermittent
17525 - Oxygen (Lambda) Sensor Heating Circuit: B1 S2: Short to Ground
P1117 - 35-10 - - - Intermittent
17843 - Secondary Air Pump Relay (J299): Short to Ground
P1435 - 35-10 - - - Intermittent
17829 - Secondary Air Injection Solenoid Valve (N112): Short to Ground
P1421 - 35-10 - - - Intermittent
17697 - Boost Pressure Control Valve (N249): Short to Ground
P1289 - 35-10 - - - Intermittent
17908 - Fuel Pump Relay (J17): Electrical Malfunction
P1500 - 35-10 - - - Intermittent

i think it has something to do with this message:
16989 - Internal Control Module: ROM Error
P0605 - 35-00 - -

Can somebody explain what's wrong?

Audi TT 2000 180Hp. (coupe).

Thanks :?


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## Wak (May 6, 2002)

its fecked!

sorry.... :roll:

so many faults there, I'd start by ensuring the battery is a good one perhaps using another one to jump the car with the current one disconnected.

then a case of looking at the ecu and fuel pump relays as there are so many shorts to ground, its unlikely all those components would have a problem together but all of them will connect to the ecu , the ecu error does look very bad and you may have been unlucky and got a duff ecu.

$20 would get you access to a workshop manual at http://ebahn.bentleypublishers.com/inde ... icket=null for 3 days and give you help in tracing the problems if you are competant enough with cars and electronics to review this.


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## Black_64 (Oct 31, 2005)

Thanks for the reply Wak.
I already have the full cd of ebahn.bentleypublishers for Audi TT.
But there is no fault code P0605.

I think i discover the problem.
it's the relay for the fuel pump. (J17)
I feel the relay clicking but when see with a testlamp, there is no voltage on it.

Tomorrow i am going to replace this relay and see what happens.

This Say's Ebahn:

_Voltage is supplied to the Fuel Pump (FP) and several components of the injection system via the Fuel Pump (FP) relay -J17-. 
For Fuel Pump (FP) relay -J17- to close, it is required that engine is turning. This means that the relay does not receive Ground (via ECM) until the ECM recognizes RPM signals_.


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## Wak (May 6, 2002)

hopefully it will be as simple as that!


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## Black_64 (Oct 31, 2005)

I reset all the fault codes but one keeps coming:
16989 - Internal Control Module: ROM Error 
P0605 - 35-00 - -

What does this mean? Is this the cpu (ecu)?

But the car starts now each time. This means it comes back.
Strange...


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## Wak (May 6, 2002)

Black_64 said:


> I reset all the fault codes but one keeps coming:
> 16989 - Internal Control Module: ROM Error
> P0605 - 35-00 - -
> 
> ...


P0605
Internal Control Module Read Only Memory (ROM) Error

With module number 10 - Engine Electronics 
Replace Motronic Engine Control Module (ECM) -J220- => page AUDI-TT-FU07-24-004-0224-71

your relay problem may have damaged something in the ecu, you could try a 10 minute battery disconnect and fault reset followed by prayers.

Then see how she behaves :?


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## ozcancak (Jul 8, 2006)

16989 - Internal Control Module: ROM Error 
P0605 - 35-00 - -

this error comes to a friend of mine after he chipped his car .... it does not go away by delating or else but never become a big problem ....

ps:
the way of the remapping was old style opening the ecu taking out the rom programming and putting it back


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## Black_64 (Oct 31, 2005)

So it's not realy a problem. Or am i mistaken?
My TT is not remapt or something else.
I was not doing anything with the car.

The strange thing is that you can connect for diagnostics. (when it happens)

First wait for the new relay and take a testdrive.
In the mean time am charging the batt. so i can exclude this.


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## ozcancak (Jul 8, 2006)

i dont know the exact meaning of this error but i can say that my friend drives his car over 2 years with this without any problem 

must be a simple thing hope so


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## John-H (Jul 13, 2005)

P0605 points to the ECM/ECU but it could be a general fault with the electrics. I'd have a prod around everwhere paying particular attention to the battery, fuse connections and multi connectors. Check for any overheated or corroded connections, earth straps etc. Salty water may have got in somewhere and be shorting multiple things together intermittently.

Check what the battery voltage falls to whilst cranking. Anything below ~8V would possibly cause faults to get logged and indicate a low charge or bad cell battery.

As you couldn't occasionally even get VAG-COM to work this either means that the power is dying in some way or there's a short on the CAN system bus or K line to the OBD port.

Have you changed anything electrical even apparently unrelated like the radio?

You could unplug the ECU and see if VAG-COM reads then become reliable. That would again suggest the ECU is causing the problem and stopping comms. Check the loom to the ECU and connectors for water etc.


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## Black_64 (Oct 31, 2005)

John-H said:


> Check what the battery voltage falls to whilst cranking. Anything below ~8V would possibly cause faults to get logged and indicate a low charge or bad cell battery.
> 
> Have you changed anything electrical even apparently unrelated like the radio?
> 
> You could unplug the ECU and see if VAG-COM reads then become reliable. That would again suggest the ECU is causing the problem and stopping comms. Check the loom to the ECU and connectors for water etc.


Ok, changed the relay but still same problem.
No i did not changed anything electrical.

Now check what does not work when it happens.

The relay J299 clicks(Secondary Air Injection (AIR) pump relay )
I think this controlled by the ECU (j220).
But i dont here the pump.

Then there is a relay j271 (Motronic Engine Control Module (ECM) power supply relay )
What is this for? when i pull it out the ECP is stil working (light ).

Tomorrow an audi dealer will read my TT and see what's wrong.
I am wondering if they can read more then i with vagcom?


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## Black_64 (Oct 31, 2005)

Black_64 said:


> tomorrow an audi dealer will read my TT and see what's wrong.
> I am wondering if they can read more then i with vagcom?


No they can't! They get the same messages. (P0605)
They don't now the problem and they sugguest to change the ECM.
They ask 668 euro for the part only. But they are not sure that the problem is solved.

Seems to me there is no big problem with the ecm because the cars drives normal when it starts.

I am thinking to open the ecm and check the inside. If i have to changed it why don't try first myself.
Maybe there are some small relay's in side and they are the problem.


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## John-H (Jul 13, 2005)

Do the VAG-COM scan with the ECU disconnected as I suggested and see if you can communicate with the other modules OK. If this works reliably and repeatedly it points to the ECU being the problem.

If you take your ECU apart you'll see something like this:










Check all the solder joints for "dry joint" condition with an eyeglass under a strong light. You're looking for cracks in the joints like the ones below. OK this is a Ford fusebox but the symptoms are the same - not the burnt out ones in the middle but the cracked ones at the sides:










The chip marked with a cross in the first picture is the 4MBit flash memory. This contains the code for the ECU.

There is a known fault with the Dashpod where the memory is incorrectly written - this can leave the memory devices with a weak imprint of the code which have trouble being read by the processor. This first shows up at low temperatures after a few years of service. I wonder if this could have happened with your ECU? I've not heard of this before but you could try warming the chip and seeing if the car starts and VAG-COM works etc., then cooling the chip with an ice cube in a plastic bag (you don't want to get the PCB wet as it will short out) or freezer spray and seeing if the cold causes the fault.

If the FLASH memory is suspect you can get the chip unsoldered and the code copied to a fresh chip (keep the chip warm when reading out). This would need to be done by someone with the necessary specialist equipment, such as a TV repair shop or electronics development company. You could also buy a replacement chip with a remap from a chip tuning company :twisted: . They would also be able to help. You'd need the ECU part number to quote. Perhaps there's one near you.


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## Black_64 (Oct 31, 2005)

John-H said:


> Do the VAG-COM scan with the ECU disconnected as I suggested and see if you can communicate with the other modules OK. If this works reliably and repeatedly it points to the ECU being the problem.
> 
> If you take your ECU apart you'll see something like this:


Ok m8, i did the test you suggested. I can communicate to the other modules without the ECU connected.
When it happens and i can't connect to the ECU but i still can connect to the other modules.

Then for the heating and freezing of the flash. After heating i can start the car.
But when i cool down the flash with a ice cube i still can't start the car.

Then notice that the ic on the left upper corner was a little warm.
After cooling this one the car starts. But i dont think this is always so (more luck).
Then try the big ic in the middle, seem to be that when i cool that the car starts. (perhaps lucky again).

I have also i question. I can buy a new ECU from Bosch (i now i guy there and can get them cheaper) but can this be used for my car? 
I have the Bosch number.
I now it has to be proged by Audi for the vin number etc... or can i do it with vagcom?


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## John-H (Jul 13, 2005)

Black_64 said:


> ... Ok m8, i did the test you suggested. I can communicate to the other modules without the ECU connected.
> When it happens and i can't connect to the ECU but i still can connect to the other modules.


Ok - that means the ECU is not dragging down the CAN bus and stopping general comms between modules - You did say before that sometimes you couldn't get VAG-COM to communicate which suggested the CAN bus was being disabled by something.

It also means of course that the ECU has a problem



Black_64 said:


> ... Then for the heating and freezing of the flash. After heating i can start the car.
> But when i cool down the flash with a ice cube i still can't start the car.


Well done  That would seem to confirm my suspicion about the FLASH.



Black_64 said:


> ...Then notice that the ic on the left upper corner was a little warm.
> After cooling this one the car starts. But i dont think this is always so (more luck).
> Then try the big ic in the middle, seem to be that when i cool that the car starts. (perhaps lucky again).


The device on the upper left corner of the photo is a voltage regulator I think. If so it would normally run warm and produce 5V to run the processor and power the FLASH. If you have a multimeter you could measure it's output voltage relative to 0V ground and see if this alters with the ice cube. If it doesn't alter then the car starting was a coincidence. I think this is likely the case as these voltage regulators are usually very reliable.

The big IC in the middle is the processor. Again I think this is not likely to be the faulty item.



Black_64 said:


> ...I have also i question. I can buy a new ECU from Bosch (i now i guy there and can get them cheaper) but can this be used for my car?
> I have the Bosch number.
> I now it has to be proged by Audi for the vin number etc... or can i do it with vagcom?


There are many varients of the ECU with code specific to the engine, ESP, and transmission etc. The Audi part number ends with two letters e.g. 8N0 906 018 AE. The last two letters denote the specific code for your car. I suspect the BOSCH unit may be generic and will not have the correct code loaded. I'm not sure if you can write the VIN number with VAG com.

If you contact a chip tuner and tell them your story they might take pity and have a standard FLASH they can give you.


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## Black_64 (Oct 31, 2005)

@John-H,

Big thanks for the help !!!

I have notice that the car always starts the first time you try after a long periode.
Maybe it is a voltage problem. I will later try to measure the 5V.

The number of the ECU is almost correct but the the last two aren't letters.
Look at my number: 8N0 906 018 Q.
Ok you are not sure that the i can use this ECM from Bosch.
I will ask the for the Audi part number.

Thanks again.


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## KammyTT (Jun 28, 2006)

check the for sale section, someone is selling a chipped ecu for Â£250 gbp


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## Black_64 (Oct 31, 2005)

KammyTT said:


> check the for sale section, someone is selling a chipped ecu for Â£250 gbp


Thanks.


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## Black_64 (Oct 31, 2005)

Ok, this i have done in the mean time.

I checked all the wiring and connectors. Put a light on the ecu connector so i can see if it gets some voltage
after turning the ignition key.
Still no luck.

Then i found a person who nows about remapping and repairing ecu.
He looked at my ecu and found some little cracks in it.
He repair this but still no luck.

Then he replaced the eprom. (Read it out and write it in a new eprom)
No luck.
Replacing the flash will help he told me.
He never has seen the fault code P0605.
That person was very nice he did not ask anything to pay. 

So now i order a new ecu by Audi and waiting to replaced it there.


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## John-H (Jul 13, 2005)

You've done well  . So you changed the FLASH device - you actually physically changed it or did you just re-burn the code back into the same device?

I thought you were onto a fix - I'm surprised it didn't work given your test with the ice cube and then warming the FLASH. You don't think it could have been a coincidence do you? How many times did you try it - was it very repeatable? I'd hate you to buy a new ECU and find it makes no difference.


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## Black_64 (Oct 31, 2005)

John-H said:


> You've done well  . So you changed the FLASH device - you actually physically changed it or did you just re-burn the code back into the same device?
> 
> I thought you were onto a fix - I'm surprised it didn't work given your test with the ice cube and then warming the FLASH. You don't think it could have been a coincidence do you? How many times did you try it - was it very repeatable? I'd hate you to buy a new ECU and find it makes no difference.


The eprom was changed physically with a newone.
The flash was not changed. They told me that it will not help.

I still keep asking myself why i get the fault code each time i put on the ignition (after a reset) and sometimes not starting.

The faultcode is there but the car is starting and sometimes i does not start.

The remap person ran a full diagnostic of the car.
Even the instrument panel and the can-bus. He did not found any faults.
So it must be the ecu.


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## John-H (Jul 13, 2005)

Well let's hope so. This is the 4MBit FLASH device however - the one marked with a cross - it's a AM29F400 device (http://www.datasheetarchive.com/Thumbna ... S78286.jpg). This contains the software code for the ECU and it's this I presume you were heating and cooling. This is what should have been changed and re-coded.










There is also a smaller EEPROM device that contains some custom information like the chassis number etc. I can't remember which one it is but it's physically much smaller.

There is no EPROM (Electrically Programmable Read Only Memory) - I presume this is getting confused with the 4Mbit FLASH device which is an EEPROM (Electrically Erasable Programmable Read Only Memory).

I'm not trying to be pedantic - just making sure :wink:

Does this agree with what was done?


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## Black_64 (Oct 31, 2005)

> There is also a smaller EEPROM device that contains some custom information like the chassis number etc. I can't remember which one it is but it's physically much smaller


It was the smaller EEPROM that was changed.
It was very small, you can barely see it.

But the flash (4Mb) was ok. They told me.


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## John-H (Jul 13, 2005)

Well, given your heating/cooling of the 4MBit FLASH caused start/no-start I'm still of the opinion that it was the seat of the problem :? . At least it also means that the ECU is at fault, so a replacement ECU will cure it  .


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## Black_64 (Oct 31, 2005)

It's getting worse. Now my TT is not starting in the morning.  
So if it's cold or hot, it doesn't start.

Now i need to turn the key several times (10, 20). 
I hope my new ecu will be there soon. For now i leave the car at home before it doesn't start at all.


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## Black_64 (Oct 31, 2005)

Audi replaced my ECU.
Now it's working perfect again. :lol:

To bad it did not get the old one back. It's a exchange part.

Total cost 706 euro. (incl. vat, work and programming).

Now i'am going out for a nice drive (i hope :roll: ).

Thanks to all for the reply's !!!


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## John-H (Jul 13, 2005)

Glad you got it going again 

I'll not forget that trail blazing bit of experimentation you did


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