No Start - No Response from ABS and Engine Control Module (helpppp!)

[SO WAGN]

Hi all,

It's my first post here. I've been a long time lurker and have to say thanks to those that have contributed to the forum because there is an amazing wealth of knowledge on this site! I'm posting today to see if anyone is able to help diagnose a no-start issue I'm having.

I have recently taken ownership of a pretty special B6 A4 1.8t Quattro Wagon who I bought off the 1st owner after he had moved onto an S5. It's had quite a lot of work done to it and is in amazing condition for its age, the owner is a member of AZ and OzAudi.

Late 2003 Audi A4 S Line 1.8t Quattro 6spd Manual. Non Canbus early model as far as I'm aware.

Mods
I'll list the mods that I feel are relevant for the purpose of this diagnosis:
Stage 3+ APR kit
Garrett GT2860R
APR Front Mount
APR TBE
Porsche Brembo BBK
RNS-E
TTS steering wheel

History
Of recent I've been getting the car going into limp mode due to a 17536 Fuel Trim - System too lean error, as well as 17522 - Oxygen (Lambda) Sensor: B1 S2: Internal Resistance too High codes. I swapped out PCV & PCR valves (thinking possible vac leak, still need to inspect check valves), as well as rear O2 sensor. I also have a mild boost leak. I had been monitoring my fuel trims and noticed that my long term idle is at around 1.5% yet part throttle had at times risen to ~21%. I also notice a +% spike when coming off throttle sometimes. This lead me to believe it is more a MAF, fuel pump or injector issue rather than a vacuum leak. MAF has just been changed, I inspected it and cleaned yesterday and I don't feel any stuttering that I would expect if the fuel pump was on it's way out.

Problem
I think these issues are separate from my latest and more significant issue. When stepping into the car yesterday, I cranked the car over and couldn't get it to start at all. The car cranks fine, and battery is testing good, but no spark? or no fuel?..

I am getting ABS, ESP and brake light showing on the dash when I try and tick it over. I've made sure it's not the steering wheel lock preventing it kicking over, and I can't see any evidence of it being immobilizer intervening. I'm also hearing the fans cycling over and over when the key is in ignition position. Battery tests ok at 12.5v.

Diagnosing
I ran VCDS and couldn't get a response at all from 01 Engine Controller test. I've checked all fuses and have inspected relays. No obvious signs of failure apart from fan relay 219 in the ECU box showing a bit of corrosion on the contact pads (internal). I tested and the relay still works, although I will order a new one. This would more than likely explain why the fans are going, but they only turn on when key is turned to ignition which is switching the relay.

As mentioned, the battery tested ok, and I tried to kick the engine over with a battery jumpstarter also and still can't get a response. I've unplugged the MAF, both O2 sensors, ABS control unit separately and all together and still can't get a response from the ECU.

Previous owner had passed on the original ECU which I swapped out and tested in the car, still no response from ECU Controller. I've also removed the RNS-E and inspected wiring. The unit was retrofitted into the car but I can't see any obvious wiring issues that might be causing the issue.

I am really hoping I have missed something very obvious.. I would have thought that if it was coilpacks or fuel pump there would be more obvious signs of failure leading up to the issue but it's quite the opposite, the car was running great just prior. Any suggestions are very much welcome, and I really appreciate anyone's input.

VCDS Scan Results
Chassis Type: 8E - Audi A4 B6/B7
Scan: 01(no communication),02,03,08,09,0F,11,15,16,17,18,36,37 ,45,46,55,56,57,65,67,69,75,76,77

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8E0-614-517.LBL
Controller: 8E0 614 517 A
Component: ABS/ESP allrad 3429
Coding: 04475
Shop #: WSC 12345
3 Faults Found:
18258 - Powertrain Data Bus: Missing Message from ECU
P1850 - 35-00 - -
18258 - Powertrain Data Bus: Missing Message from ECU
P1850 - 35-00 - -
01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30
35-00 - -

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8E0-820-043.LBL
Controller: 8E0 820 043 AC
Component: A4 Klimaautomat 1424
Coding: 00000
Shop #: WSC 00000
1 Fault Found:
01206 - Signal for Duration of Ignition; OFF
27-00 - Implausible Signal

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 8E0-907-279-8E2.LBL
Controller: 8E0 907 279 F
Component: int. Lastmodul RDW 0517
Coding: 00001
Shop #: WSC 63251
1 Fault Found:
01312 - Powertrain Data Bus
79-10 - Please Check Fault Codes - Intermittent

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8E0-959-655-84.LBL
Controller: 8E0 959 655 B
Component: Airbag 8.4EP 3002
Coding: 0010602
Shop #: WSC 63251
No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 8E0-953-549.LBL
Controller: 8E0 953 549 R
Component: Lenksáulenmodul 1102
Coding: 02042
Shop #: WSC 00000
No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8E0-920-9xx-8E2.LBL
Controller: 8E0 920 900 L
Component: KOMBI+WEGFAHRS. RB4 D37
Coding: 11700
Shop #: WSC 62515
WAUZZZ8E64A125051 AUZ6Z0C0295772
3 Faults Found:
01314 - Engine Control Module
49-00 - No Communications
01316 - ABS Control Module
49-10 - No Communications - Intermittent
01303 - Telephone Transceiver (R36)
49-00 - No Communications

-------------------------------------------------------------------------------
Address 37: Navigation Labels: Redir Fail!
Controller: 8E0 035 192 C
Component: RNS-E HIGH EU H50 0650
Coding: 0301115
Shop #: WSC 06335
3 Faults Found:
00858 - Connection; Radio ZF Output to Antenna Amplifier
011 - Open Circuit
01316 - ABS Control Module
004 - No Signal/Communication - Intermittent
01044 - Control Module Incorrectly Coded
000 - -

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 8E0-959-433-MAX.LBL
Controller: 8E0 959 433 AS
Component: Komfortgerát T01 1210
Coding: 07104
Shop #: WSC 21000
No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: Redir Fail!
Controller: 8E0 035 192 C
Component: RNS-E HIGH EU H50 0650
Coding: 0301115
Shop #: WSC 06335
3 Faults Found:
00858 - Connection; Radio ZF Output to Antenna Amplifier
011 - Open Circuit
01316 - ABS Control Module
004 - No Signal/Communication - Intermittent
01044 - Control Module Incorrectly Coded
000 - -

End --------------------------------------------------------------------------------------------------

[SO WAGN]

**Update**
For those interested, I know this has been such a hot topic :/ , I'll give an update.

I've swapped out the ABS control module, recoded and found that it was not the issue. I tested the wiring harness to the ecu and I am getting steady 12.4v on the pins that require it on the ECU (http://www.audizine.com/forum/showth...=1#post8490980)

I've since inspected my ECU which is APR Stage 3+ chipped and I can't see any obvious signs of failure at any capacitor or transistor. All the solder joints look good. Upon bench testing the unit and connecting straight to the K Line, I still don't get a response from the ECU.

I've now got a used ECU (same part number) and was wondering if it is actually possible to swap over the EEPROM Immobiliser chip between the two ECU's so that I don't have to worry about flashing the new immobiliser chip at all. I know of other Audi ECU's that have done this with no problem but I'm wondering if others here have done it before successfully?

Further to this, is it possible to just re-solder my APR chip to the new ECU unit also?

[diagnosticator]

It is likely that the K line diagnostics transceiver chip is not functioning for some reason. It's not uncommon for IC's to arbitrarily stop working. A bad K line transceiver won't disable the ECU normally. However, the K line transceiver is part of the CAN transceiver both on a common chip. The K line is not the only comms effected in your case. The power train CAN transceiver in the ECU is not talking to the CAN buss either. That is why there are missing message/no communications DTCs stored is the other controllers on the power train and comfort CAN buses. A bad CAN/K/L line transceiver chip is consistent with the symptoms occurring. Since the engine won't start, then there is also likely other problems with the ECU hardware preventing spark and or fuel injector operation.
The APR chip and the immo chip can be moved to the new ECU, but the soldering work is fussy and takes skill. Unless you have a lot of electronics construction/repair experience, I recommend having the chips swapped by an electronics repair shop instead of a DIY.

[SO WAGN]

Thanks for the response. That makes sense.

I just tried the donor ECU and it fires up the car but immobiliser intervenes as expected.

Moving the immobiliser chip and the APR chip seems like the simple choice for me at this point. I've got a lot of experience with electronics so I'm sure this will be ok.

I'll post the outcome, I should get around to this in a couple of days.

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[G-Ride]

ECU Supply Relay?

[SO WAGN]

ECU Supply Relay?

Thanks, this would be one of the first things to check when dealing with similar symptoms. Also obviously going through all fuses would be next.

I had inspected my ECM relay early on and tested with a multimeter for continuity and it's working fine.

I believe diagnosticator has got it right though. Even when trying to connect straight to the k line I can't get a response with my existing ECU. I was considering trying to fire it up in boot mode but with the APR chip I am hesitant to flash it.

I'll be swapping the immobiliser chip into the new donor ECU first, if it works I'll more than likely move the APR chip over shortly after. I've worked with smaller SMD's before so I'll just take a lot of care when doing it.


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[Arnie91]

Have you tried changing the fuses?

[SO WAGN]

Have you tried changing the fuses?

The problem lies with the ECU after bench testing it.

But yes, prior to confirming this I had checked all relevant fuses and tested with multimeter.

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[SO WAGN]

Just in case anyone stumbles across this thread in the future, I thought I would update.

The problem was with the ecu as mentioned above. I ended up getting a donor ECU and swapped the immobiliser eeprom chip over from my fried APR chipped ecu to it.

The following video shows the location of the chip.

For anyone interested in doing this, my only advice is to be very careful when lifting the chip not to damage the pads on the board but using excessive force. Let the heat do the work for you and apply very gentle pressure. Also be sure not to bump any of the other components on the board whilst the solder is hot.

https://youtu.be/-y7mSkMhyjU

Next on the cards for me is to get my car custom tuned, I was never really happy with the APR stage 3+ tune due to fuel starvation issues. I'm looking into a conservative E85 tune and will be upgrading to a DW fuel pump and big injectors.

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