Water Damaged ECU: Repair or Replacement?

Hi,

During the heavy rain we had here last Tuesday evening, my control unit got flooded.
Parked the car in the evening, everything seemed fine. The next morning, after it had rained, I tried to start it.
=> The engine wouldn't start. I then took another car and went to work.
In the evening, I connected my laptop and checked with VAG-Com, but there were no error codes.
=> Restarted, engine won't start, checked again with VAG-Com.
=> ERROR: Too many communication errors.
=> My car was towed to my father's garage so that it could be checked again with a VAG-Com diagnostic tool.
Communication is possible again, but the engine still won't start.
Control unit removed, it's completely full of water.

So far, no change; the engine still won't start.

My questions:
How likely is it that the engine control unit (ECU) failed due to the starting attempts while submerged?
is?
Is the control unit internally or externally protected against short circuits or overloads?

Simply carefully dry it with a lint-free cloth and a hairdryer (making sure not to use excessive heat). If there isn't too much tension on the material, then hopefully nothing has happened.

Most electronic devices operate with very low voltages, typically 3.3V or 5V, or something similar. Look for a small glass fuse; it will look like a small glass tube, approximately 2cm long and 3mm in diameter, with two metal contacts on each side.

In addition, rainwater conducts electricity very poorly! It only becomes dangerous with capacitors, which are quite sensitive to short circuits.

But even if it's not protected: I have already frequently submerged my PC and other devices completely in water (even while they were running), then turned them off, dried them, and as you can see, it still works .

Good luck!

Hi,
STG might still be alive.
You've already broken it down .

To ensure safety, rinse the circuit board with distilled water to prevent any moisture-attracting residue from remaining after it dries.
Dry the circuit board in the oven at a temperature of 50-80°C.

Dry the casing (due to the potential contents of the pressure equalization opening) in the oven as well.

Assembling -> Good luck!

Best regards, Rudi.

Hi,

@Kenny

What exactly do you mean by 'not letting it get hot'?
I was actually thinking of trying to dry it in the oven at around 50°C, or is that already too much?
Too warm?

@Rudi,
I was probably too slow.

Don't worry, all the electronics used in the vehicle are designed to withstand temperatures up to +125°F.

Therefore, as Rudi writes, place it in the oven at 50-80°C and let it sit for a long time (at least 4 hours). This temperature definitely won't damage the electrical components (have you ever measured the internal temperature of a car in the summer?).

With a little luck, it will start working again.

I've actually had success with baking electronics that have been water damaged on several occasions.

CU Gremlin.

Hi,
Just to reassure you further.
It also gets very hot for the vehicles inside the paint booth.
Why did that thing actually sink? Were the drain holes clogged with leaves?

Have fun grilling...

Regards,

Andy.

Hello Achim,
As already mentioned, there are good chances that the SSD will function normally again after drying. However, act quickly before corrosion forms. For example, I once completely submerged a mobile phone (it was totally gone underwater, yes, you can laugh ). After drying it in a climate chamber, everything worked perfectly again.
Here's the translation:

'I also have a question: Was the flooding caused by the water tank?'

Hi,

Thank you for the answers.

For further information, the control unit had been 'optimized' and coated with some kind of black substance.
sealed. Water was coming in from the top, specifically where the black plastic of the outlets meets the surface.
The aluminum of the housing is protruding outwards again.
Was die Ursache für die Ueberschwemmung war kann ich noch nicht sagen. In the morning, the...
The watering can is definitely empty.

By the way, I didn't install the engine control unit (ECU) myself. My dad is on his way to the tuner.
He should take a look at that.

Hello Achim,

Achim wrote:

Was die Ursache für die Ueberschwemmung war kann ich noch nicht sagen. In the morning, the... The watering can is definitely empty.

"In my A3, there was a huge amount of dirt and debris accumulated behind the plastic wheel arch liners, which then blocked the drain from the windshield washer reservoir. I don't know your car, but it might be similar in your case."

Best regards, Rainer.

Sure, here is the translation of the text from German to English:

"Hi Gremlin,"

Gremlin wrote:

Don't worry, all the electronics used in the vehicle are designed to withstand temperatures up to +125°F.

Objection!

According to the BMW standard, automotive electronics should adhere to the following specifications:
Ambient temperature:

-40°C to +90°C functional temperature (electronics only).
-30°C to +70°C: Full functional temperature range (combining electronics and mechanics).
-15°C to +60°C, full functionality within specifications.

and even more strictly, the maximum storage temperature (in packaging!).
-13°F - +131°F

At temperatures above +125°C for an extended period, several components (especially electrolytic capacitors) or solder joints (particularly in the surface mount device area) are likely to fail.
So, the 50°C mentioned by Rudi is definitely acceptable and should not pose any problems for any automotive-grade component.
WARNING: Standard "crafting" components often cannot withstand the temperature range mentioned above!

The standards of other car manufacturers are not quite as strict as those of BMW, which is why I only mentioned them (VW has upper limits that are 5-10° lower).

Hi Bertil,

-40°C to +90°C functional temperature (electronics only).

Suitable for components with a maximum permissible operating temperature of 125°C.
(Self-heating in a closed housing).

A maximum storage temperature range of -25°C to +55°C seems reasonable, in my opinion.
When it comes to storing parts for years, it certainly has its advantages.
Side effect: the warehouse workers might drop the part out of fright.


Best regards, Rudi.

Hi Rudi,

Rudi wrote:

-40°C - +90°C functional temperature (for electronics only). Suitable for components with a maximum permissible operating temperature of 125°C. (Self-heating in a closed housing).

In operation, that's correct. The maximum component temperature (for semiconductors) can reach 125°C, but the entire component should be significantly lower than that. I would avoid heating an entire assembly to 125°C, as various plastics (used for housings or similar) certainly wouldn't withstand that temperature. Also, electrolytic capacitors have a much smaller operating temperature range.

At a total component (STG) temperature of 125°C, you will experience such high expansion values that various solder joints (or surface mount device components) are likely to break and become pre-damaged. Failure is almost guaranteed.

Quote:

A maximum storage temperature range of -25°C to +55°C seems reasonable, in my opinion. when it comes to storing parts for years...

"The parts are usually not stored for very long, so this relatively low value is also surprising. The storage tests are conducted at maximum temperatures for over three weeks, with a cycle of 8 hours each time between the minimum and maximum temperatures – which puts quite a bit of stress on the components!"
For ET storage, other specifications are also planned (-15°C to +45°C).

Quote:

...and certainly has a pleasant... Side effect: the warehouse workers might drop the part out of fright.

If I were to unexpectedly touch a device that was "hot" at 55°C, I would still probably be startled .
By the way, the devices are not packed individually but in ESD-protected (carrying) boxes. The warehouse worker should not touch the individual device (and is even prohibited from doing so - because we have visible components). Only at the assembly line are the devices taken out of the collective box and installed. That's the theory .

In the military and medical fields, there are even more stringent specifications depending on the application. Some components might be able to withstand temperatures of up to 125°C throughout the entire device. However, these components only cost "slightly" more than the automotive parts .

Hello,

Don't worry, the electronic components are quite robust. They need to withstand a reflow soldering temperature of approximately 240 degrees for a short time. So, it's fine to dry them in the oven at 80 degrees Celsius for a few hours. If electrolytic capacitors are used in a module, they should be at least rated for 105 degrees Celsius. Good circuit boards typically only fail under continuous stress exceeding 125 degrees Celsius. I'm sure that the plastics will deform before the unpowered electronics give up.

Best regards,
Christian.

chris11 wrote:

So, it's safe to dry them in the oven at 80 degrees Celsius for a few hours. If electrolytic capacitors are used in a power supply (STG), they should be rated for at least 105 degrees Celsius. Good circuit boards also only become damaged under continuous stress exceeding 125 degrees Celsius. I'm sure that the plastics will deform before the unpowered electronics fail.

Hello.

I see it similarly, but I still wouldn't just put the unopened package of yeast directly into the oven.
Because (as already mentioned): who knows what conductive or "semi-conductive" deposits rainwater has left behind in the STG .

Therefore, open the STG (presumably a container), rinse the circuit board again with verschandeln water and, if possible, gently brush it. Dab off the remaining rinsing water from the circuit board with a kitchen towel. And then, place it in the oven.

'Disassembling is clear; it seems obvious based on my understanding of the operation.'


But DO NOT rinse with water!

Not even with distilled water. Besides the fact that it would be counterproductive, it doesn't really verschandeln effectively either. There are suitable materials for that purpose.

And it's crucial to bake them for a *very* long time. Multilayer PCBs absorb an incredible amount of water, and so do the components. Manufacturers even provide 'baking instructions' – if you open a package and the humidity indicator strip has turned color, that means baking is necessary.

Otherwise, I'm assuming we're dealing with fairly robust component types. After all, we're in a car, and a component that can only withstand temperatures of 70°C or less would fail even in the summer if it's just parked in the sun. Depending on the application, the electronics are typically operating within a temperature range of 75-140°C. And I mean *in operation*. For example, microhybrid control units can be found directly in the transmission or on the pump (VP30/44).
Individual integrated circuits (ICs), such as power amplifiers or CAN bus drivers, may have maximum operating temperatures of up to 175°C! (Of course, they are not meant to operate at that temperature continuously...).

Set the oven to 50-75° and let it bake overnight...

CU Gremlin.

Hi,

Gremlin wrote:

Otherwise, I'm assuming we're dealing with relatively robust component types; after all, we're in a car, and a component that can only withstand temperatures of 70° or less would likely fail even in the summer if it's just parked in the sun.

I wasn't talking about individual components, but rather the entire assembly.
By the way, even if the interior of the car reaches temperatures of around 80-90°C, the temperature inside the car radio is already about 10-20°C cooler (measured in a BMW 7 series).

Quote:

Depending on the application, the electronics are typically located within a temperature range of 75 to 140° Celsius – and this is while they are in operation. For example, microhybrid control units can be found directly in the transmission or on the fuel pump (VP30/44). Individual integrated circuits (ICs), such as power amplifiers or CAN bus drivers, may have permissible operating temperatures up to 175°C! (Of course, they are not meant to operate at that temperature continuously...).

I don't have the exact specifications for the engine compartment (not the water tank!), but if my memory serves me correctly, and Alzheimer's hasn't completely taken over, it was somewhere between 100 and 120°C ambient temperature.

Quote:

Set the oven to 50-75° and let it bake overnight...

Absolutely agree. In the meantime, I would check if there are any deposits from the water on the circuit board. Electromigration will manifest itself later on its own, and it will eventually cause you a lot of trouble.