Car starts easily but dies immediately - 2005 A4 Avant 1.8T Quattro

[mjf1080]

Car has been sitting for a month at a time since covid, no issues except for dead battery that I would have to jump once in a while. Bought new battery Jan 4, last drove Jan 11, installed trickle charger that day to keep new battery alive without driving much. The car has literally had almost no issues in the 12 years I’ve had it, and had no current issues before the current one started.

Tried to start it a few days ago, first time since installing trickle charger a month ago. First, noticed red light showing alarm engaged wasnt on, remote didnt work either, opened door with key, no door open chime, but interior lights came on. Key in ignition, turn to on, hear the fuel pump engage, cluster is dark except air bag and esp indicator lights on. Start the engine, sounds like it fires up easily, but dies after 1-2 seconds. Tried to rev the engine, which it lets me do but it dies just as quickly. Stereo says “safe” but cluster doesnt. I have since entered the code in the stereo and it now operates normally. Climate control does not turn on except when defrost is pressed. It has a stage 1 tune and I tried to disengage that using the cruise control knob and that didnt work - usually the check engine light flashes slow and then fast when tune initiated, and I had no check engine light in this case.

I cleaned battery terminals and tested voltage at 12.05 volts, but of course not able to test with engine running. I have disconnected the battery leads and connected them together for 15 minutes, made no difference. I opened the ecu compartment (part way) and no water or signs of moisture, 40Amp fuse looked fine but it was too tight to test), and I pulled many of the fuses at driver’s left and didnt see any issues.

I cant find my scanner… toddlers hid it from me, so I dont have any codes until I buy a new one. Any suggestions on what to buy?

Any help much appreciated. Hoping to avoid flat decking to the dealer.

Thank you very much.

[Ozone510]

I'd say check the engine jet suction pump and any vacuum lines. Maybe clean out/ check your intake.

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[Cybersombosis]

Sounds like an immobilizer issue. Is the battery fully charged?

[mjf1080]

I had assumed if it will turn over the starter motor that it’s not dead, but checking the voltage I got 12.06 volts, which sounds low. Maybe my battery tender only maintained the battery at 12v when it should be 12.20-12.60 volts? And maybe the car is choosing which systems to power given the low voltage?

[Cybersombosis]

Weird things happen when your battery is low. Did it struggle at all when starting? Your cluster should light up with the ignition on with all the warning lights coming on at the same time. At any point do you see the immobilizer symbol on the cluster show up when starting the car?

[Mike Tries]

The ECU doesn't like to operate below 12 volts, right? Isn't that why we need to use battery tenders when flashing? Could you try hooking up another battery, or just jump start it?

[EuroxS4]

Check with VCDS immo MVB in the cluster. My money is on immo being active.

[mjf1080]

Thanks for all the tips so far. Jumped with my wife’s car and now have full cluster plus it says SAFE beside the odometer, and makes an alarm chime. Is there a reliable way to get out of SAFE mode? I’ve tried a bunch of things and no luck yet. I don’t have vcds but maybe I should just bite the bullet and buy it, but I’m planning to sell the car very soon. Obviously I need to address the battery, trickle charger, and possibly alternator once I can get the car running.

[grayjay]

Safe on cluster and alarm chime sounds like a trigger immobilizer. I wonder if your ignition transponder receiver might have become damaged, so that it is no longer recognizing the key transponder chip. No change to the key that has always worked?

[mjf1080]

Correct, no change to the key, and all 3 keys have the same response in the ignition. I wonder if the transponder receiver needs to be re-programmed, like how the stereo needs a security code to exit safe mode?

[EuroxS4]

Or you have a bad reader coil.

[grayjay]

Long dead battery should not have erased the key transponder coding, I agree that the reader coil in ignition is likely bad. I am not sure how to test if the coil reader is working, but likely cheaper to try replacing that yourself rather then having car towed and diagnosed by a shop.

That said, it you do want to also try re-adapting the keys to the car, you will need to retrieve the SKC per;
https://sites.google.com/site/imnuts/
once you have the SKC, the key adaptation can be done with VCDS or using downloadable VAG K+CAN Commander software;
https://www.audizine.com/forum/showt...y-fob-now-what!

If your battery is only at 12.05v, might also be good idea to get it charged above 12.5v to completely eliminate possibility of issues due to low voltage.

[mjf1080]

I appreciate all the help. I’ve decided to give up and take it to the dealer. It sounds like either coil reader (replace ignition incl keys), or something in the cluster (either immobilizer module or the whole cluster), both cases make me scared about adaptation codes that I’ll need, and since I dont have VCDS, the safer route is just to tow it to the dealer and get it sorted in one spot. I’ll report back with an update when fixed. Thanks again.

[Ozone510]

I appreciate all the help. I’ve decided to give up and take it to the dealer. It sounds like either coil reader (replace ignition incl keys), or something in the cluster (either immobilizer module or the whole cluster), both cases make me scared about adaptation codes that I’ll need, and since I dont have VCDS, the safer route is just to tow it to the dealer and get it sorted in one spot. I’ll report back with an update when fixed. Thanks again.

Keep in mind if you get new keys cut, you're going to have to carry around the old set to unlock your glovebox, lock it, to do the folding seat lock, child lock, and trunk! I forgot this and it was not fun to find my seats locked up right!

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[grayjay]

I think the ignition transponder reader coil can likely be replaced without needing to change the lock &keys or mess with any of the key transponder adaptation. Changing the coil could be a fairly simple fix that you can DIY,

[Ozone510]

I appreciate all the help. I’ve decided to give up and take it to the dealer. It sounds like either coil reader (replace ignition incl keys), or something in the cluster (either immobilizer module or the whole cluster), both cases make me scared about adaptation codes that I’ll need, and since I dont have VCDS, the safer route is just to tow it to the dealer and get it sorted in one spot. I’ll report back with an update when fixed. Thanks again.

Also on the note of "more" expensive. If you purchase a VCDS ($199.99 ON AUDIZINE BNIB), you will save money and have a new tool that is invaluable when troubleshooting.

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[Cybersombosis]

If only you were a little closer.

[mjf1080]

Also on the note of "more" expensive. If you purchase a VCDS ($199.99 ON AUDIZINE BNIB), you will save money and have a new tool that is invaluable when troubleshooting.

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I totally agree but I was already planning to sell the car and I have 3 kids under 3 so no time to tinker. I’m also in Canada so it ends up being like $400 CAD after shipping for VCDS, and doesnt guarantee I dont still need to tow it to the dealer in the end.

[mjf1080]

I think the ignition transponder reader coil can likely be replaced without needing to change the lock &keys or mess with any of the key transponder adaptation. Changing the coil could be a fairly simple fix that you can DIY,

Reader coil replacement is sold with the ignition lock cylinder (incl new keys, minus remotes) and carries a warning that it needs to be coded. I’m seeing it listed for $320 and $500 (plus VCDS, I’d be into it for $700-800) without knowing that’s the fix, which is starting to sound like what the dealer might charge me to fix the problem for sure, hopefully??

[Ozone510]

Reader coil replacement is sold with the ignition lock cylinder (incl new keys, minus remotes) and carries a warning that it needs to be coded. I’m seeing it listed for $320 and $500 (plus VCDS, I’d be into it for $700-800) without knowing that’s the fix, which is starting to sound like what the dealer might charge me to fix the problem for sure, hopefully??

I'll pray for you man, my girl and I just chased electrical gremlins for the past few months and dug a $3K hole for her TT MK2, but it's finally sorted. Hope it's simple for you, if anyone local to you can lend a VCDS, you'd be saved and can further diagnose. Some people charge small fees to rent these out BTW.

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[mjf1080]

Car is at the dealer, confirmed instrument cluster is bad. Part is discontinued, so need to repair or source used. Does anyone have any recommendation on repair? Thanks in advance.

[walky_talky20]

A used cluster would be the best repair.

My recommendation is to use a tool like K+Commander or similar to dump the SKC from the new cluster and existing ECU. Then program everything by the book using VCDS.

[Cybersombosis]

We have a used cluster for sale but you’d need to get it programmed. PM me for details. Do you have a cheap $10 eBay VCDS cable and a PC? That’s really all you need to program everything. The software can be had for free. If you were ever in Victoria, I’d say pop on over the shop but unfortunately you need the car with the cluster in order for the cluster to be programmed.

[mjf1080]

Update: big thanks to @cybersombosis for hooking me up with a cluster.

Dealer says cannot communicate with old cluster so cannot retrieve old SKC. Does anyone have any ideas how to get the SKC from a different source?

Thanks.

[Cybersombosis]

Use Vag K Commander to get the SKC from the ECU.

https://sites.google.com/site/imnuts/

[EuroxS4]

Update: big thanks to @cybersombosis for hooking me up with a cluster.

Dealer says cannot communicate with old cluster so cannot retrieve old SKC. Does anyone have any ideas how to get the SKC from a different source?

Thanks.

SKC can be pulled from 24c08 eeprom on the pcb. Would need to remove and disassemble the dash to do it. But it's garanteed. Vag K commander can give false skc especially when not using original cable to read data.

[mjf1080]

SKC can be pulled from 24c08 eeprom on the pcb. Would need to remove and disassemble the dash to do it. But it's garanteed. Vag K commander can give false skc especially when not using original cable to read data.

Thanks. Would you be able to elaborate on the process to read it once the cluster is disassembled?

[walky_talky20]

Use Vag K Commander to get the SKC from the ECU.

https://sites.google.com/site/imnuts/

I've used this process (and the excellent write-up!) many times. Works great!

[EuroxS4]

Do not disassemble the dash, should be able to pull on the bench via obd connection. Just be careful, crypto dash is not cheap to repair.

[promet]

I had a similar issue with starting and the engine cutting out * completely * a little while back. turned out, for my issue, it was a failed ECM/PCM relay ( J271 ECM power control relay ), the oem part originally marked ' 219 ' in the ecu box i believe. This solved that particular issue for me. I keep a spare in the trunk.

[Cybersombosis]

Turns out his cluster was bad. The dealership was not able to extract the SKC from the ECU so the OP had to buy a cheap VCDS cable. On the phone, I walked him through how to pull the SKC using the IMNUTS link above then ran him through the process of adapting the Immo to the cluster and it all worked out. He was able to sell his car for $15000 Canadian which is just astronomical. I was gobsmacked when he told me.

[EuroxS4]

It comes down to market and how badly someone wants the car. Gald he was able to get it sorted out. Avants are a beautiful thing for sure.

[Cybersombosis]

Yes it was a manual car, Avant, USP with 128km on it (80k miles). He sure found the right person who paid his asking price. We just sold a 2004 forest green sedan 3.0 we restored with 111km (70k miles) for $7750, half the price of the Avant and we thought we were pushing it.