Fault Code 01206 (Ross Tech is No Help)

[arjun90]

Is Fault Code 01206 prevalent on the Audi A6 C5's? This fault code just recently surfaced up. AC is working perfectly fine, however, this code just appeared on my scanner. I have a state inspection to do very soon.

I replaced the battery yesterday. Also, throughout the last couple of days the battery (old) was disconnected and reconnected several times.

Ross Tech did not elaborate much, and I don't want to be unnecessarily swapping out parts unless there is something legitimately wrong. Is it a false-positive?

[arjun90]

Will this code eventually go away?

[4rings2turbos]

Best way to find out is to clear it and see if it comes back. Low voltage situations can make modules throw codes very easily. What did it say it was related to?

[4rings2turbos]

Will this code eventually go away?

Depends on what it's related to. Many MILs will self clear if the issue clears up like misfires, many won't self clear if they're very important, can't think of an example right now, but airbag lights won't self clear.

[arjun90]

I cleared it a couple of times today only to see it come back after starting up the vehicle and running the AC for a couple of minutes. I don't know if the information on the ECU is cached. However, the previous battery (6 years old) was replaced yesterday. The new battery was installed just a little over 24 hours ago. This morning the car had a bit of hesitation during its first cold start (with the battery installed), but it did eventually start up.

After driving 30 miles, CEL has not come on yet, but according to OBD Readiness, the Sensor Heater is showing a fault (denoted by '1'), there is no fault code yet on the O2 sensors. Trying to pass the NYS inspection, they only allow one fault code, and I'm pretty sure the only fault code last was pertaining to the catalytic converter (Heater Element). I should be able to get by as long as the HVAC Fault Code is out of the way.

Current OBD Readiness: 01010001

[4rings2turbos]

I'd recommend trying to survive the heat until you pass your inspection if the code comes up with the AC on only.

If you want to REALLY reset everything then disconnect the terminals from the battery entirely and hold them together to let all the power drain from the ECU. Probably already did so if you had the battery disconnected for a while though. That clears the ECUs memory for DTCs. Of course you'll then have to drive whatever distance it is for the ECU to set readiness.

[arjun90]

Thanks, I do want that fault code to eventually go away.
The other day AAA came over to diagnose the old battery (when it was still connected). While troubleshooting, he disconnected the positive first and reconnected the negative first. Its always the other way around. I have no way of determining if this was a potential cause or if it could have been some other isolated reason. Do you think the action of the AAA person could have caused this?

I didn't check for fault codes prior to today, thus its really hard to tell.

I have to rebuild the majority of the front suspension later this week (parts have yet to arrive). I wonder if the current state of the suspension has something to do with this as clearly, the car is in desperate need of repair on the front end. It's been rough handling in recent days (and last several months). Had an usual warm up in recent weeks here in NY.

Edit: at one instance, the low voltage fault code appeared on the scanner (and this is with the New Autocraft Battery); upon erasing the code, it only reappears if I disconnect the negative terminal and reconnect it again.

I'd recommend trying to survive the heat until you pass your inspection if the code comes up with the AC on only.

If you want to REALLY reset everything then disconnect the terminals from the battery entirely and hold them together to let all the power drain from the ECU. Probably already did so if you had the battery disconnected for a while though. That clears the ECUs memory for DTCs. Of course you'll then have to drive whatever distance it is for the ECU to set readiness.

[4rings2turbos]

As usual you're overthinking it :)

Suspension is guaranteed 100% not related, as well as the order in which you remove the terminals.

;)

If you clear it and it comes back then there's an issue that needs to be addressed with a part, a sensor or wiring.

Just looked up the code, looks like VCDS did indeed give you your answer. It's not that it's an HVAC issue, it's a voltage/time issue with ignition off. You ignition switch could be the issue OR you have a voltage draw that is draining your battery with the car off. You can find the draw by measuring current drain with an amp meter and pulling fuses to find out which one is giving an issue.

My advice though is that if it doesn't come back now that you've finished fiddling the battery (leave it alone now) then it was simply due to low voltage.

[arjun90]

I noticed a thin coating of Petroleum Jelly and Dielectric Grease on the positive terminal on the battery, that shouldn't trigger low voltage

I somehow managed to get to 01000000, the fault code for the 02106 was still there though (01 stands for the Heater element / Catalytic converter), cleared it and the readiness quickly reverted back to 01010000 indicating the AC fault again

I also tried swapping out the 30A fuses

As usual you're overthinking it :)

Suspension is guaranteed 100% not related, as well as the order in which you remove the terminals.

;)

If you clear it and it comes back then there's an issue that needs to be addressed with a part, a sensor or wiring.

Just looked up the code, looks like VCDS did indeed give you your answer. It's not that it's an HVAC issue, it's a voltage/time issue with ignition off. You ignition switch could be the issue OR you have a voltage draw that is draining your battery with the car off. You can find the draw by measuring current drain with an amp meter and pulling fuses to find out which one is giving an issue.

My advice though is that if it doesn't come back now that you've finished fiddling the battery (leave it alone now) then it was simply due to low voltage.

[glennda5id]

What year is your car. Are you talking 01206 in the HVAC ECU?

[arjun90]

2004, A6 3.0L Avant Quattro

That's correct 01206 in the HVAC ECU (AC Unit)

What year is your car. Are you talking 01206 in the HVAC ECU?

[arjun90]

Possible Relay Problem? Something drawing power even when the car is off?

Interior cabin is hot especially during this time of the year, have it parked in the shade as much as possible

[glennda5id]

That AC module code will not illumate the check engine light or have any impact on passing an emissions check. Looking at Alldata for a 2002, 01206 can be due to replacing the battery or an issue with control module J285 or a wiring issue.

[rollerton]

Seriously. Don't worry about it. Your car will probably store a variety of error codes related to nothing in particular and many times they have no significance and have no effect on anything. And for the most part the only errors that will trigger a CEL are 1. Related to emissions. 2. Will impact safety, reliability, driveability or economy 3. can cause/ indicate failure of a part that will lead to either 1 or 2.
There are literally thousands, or tens of thousands of errors that you should probably not worry about.

[arjun90]

I'm going to try this--disconnect both terminals to the batteries, insert key into ignition without battery connected (turn key towards on and off). Came across this on the VW forums. Car should be able to pass state inspection regardless.

From what I've been told, there is a one relay in the ECU compartment and the other beneath the dashboard which may need replacing (either or) if that code doesn't eventually disappear. Otherwise vehicle is functionally sound.

Btw, are the struts / tie rods ever inspected as part of the state inspection, or is just the brakes and Air Bag System?

[arjun90]

Have you ever seen water / debris accumulated beneath the battery tray? There was discussion somewhere stating that overtime stuff collects near the plenum drains, water may accumulate and get close to contact with delicate electrical components. Lots of speculation here, but I'd want to further check as I did remove the older battery to check the center bolts of the steering rack (which were nice and snug by the way); I did not however, remove the battery tray (no visible rust either. on the periphery). I blew compressed air and used a vacuum for collecting whatever gunk has accumulated near / around the battery area before installing the new battery. I'm hoping my actions did not indirectly cause this fault code to generate.

[4rings2turbos]

If the drain plugs and the entire area fills with water between the firewalls it can back up into the passenger footwell.

[arjun90]

Thanks, I guess I can eliminate that possibility then. It was quite a common thing in older VW models though. Will be checking the electrical connectors today for any possible short or corrosion. I still think the moisture may have found its way into one of the connectors. Ironically, a couple of the fuses I had touched were damp, felt wet, not sure if this was as a result of the weather we had here in recent days. No fault codes on the fan control module, nothing pertaining to J285

That scanner which Julex recommended last year did not disclose anything related to this http://wiki.ross-tech.com/wiki/index.php/01317
Thus, definitely an isolated issue

From the previous owner, several years ago, the ECU had to be replaced because water had somehow apparently seeped into the enclosure.

If the drain plugs and the entire area fills with water between the firewalls it can back up into the passenger footwell.

[ovitemp]

Battery can log this fault
Few days ago I found my battery drained, 2.5 V only. I didn't found what the problem was, I suspect the alarm was the problem or maybe some lights. Anyway, after an insufficient battery charge, I tried to start the engine without success. The starter couldn't rotate at all the engine and voltage was visibly dropping. I understood that the battery needs a good charge, so I did a full 100Ah charge.
Since then, everything went fine. Trying to find what drained the battery I did a scan. Many faults was logged because the voltage drop, nothing indicated what the problem was. I cleared the faults.
Now the strange thing is that 01206 was logged again and again in the HVAC module. I cleared the fault few times.
I decided to scan again for faults in the next days to see what happen.

[Danzzo]

Wrong thread lol