Power Issues/Seems to be related to ESP/ABS -- Audi s4

[m.s4]

So recently I have been experiencing some really weird symptoms in my car with my HFS-3.

Any time I get the ESP to turn on, or get substantial wheel-spin with ESP off the power flashes. The gauge goes dim except for the yellow water level light.

-Grounds are separated
-All wires have been double checked for proper placement
-water level sensor is unplugged

I didn't have these issues in the dry (lots of snow in MN since nov).
It also does it if i have the system off. The yellow light will come on.

It doesn't happen if I unplug my abs/esp fuse. I am investigating the problem being my car's wiring, but thought I would post here for some insight.

Thanks,
Mark

[Richard L]

This problem has mde easier for me as you have given me some clues.

If the gauge goes dim, it is due to the main power supply into the system, ie, the red wire from the 4-way power plug. As the yellow led's supply is regulated to 5V internally it will not be affected by a noisy 12V supply.

Is it possible to find another loaction for the red wire (molex)? It can be connected directly to the battery. The system's will not drain power until the ignition swicth is at the "run" position.

[m.s4]

Originally Posted by Richard L

This problem has mde easier for me as you have given me some clues.

If the gauge goes dim, it is due to the main power supply into the system, ie, the red wire from the 4-way power plug. As the yellow led's supply is regulated to 5V internally it will not be affected by a noisy 12V supply.

Is it possible to find another loaction for the red wire (molex)? It can be connected directly to the battery. The system's will not drain power until the ignition swicth is at the "run" position.

I will run it directly to the battery and see.
It goes to the same terminal as the other red ignition wire from the "Ecu" wires.

Would this cause the yellow light to come on when the entire system is off. (Blank gauge, then only the yellow light comes on even the the whole system is turned off.)?

[Richard L]

The main supply tio the system is from the molex connector. The other red wire (yellow harness) merely power on an onboard relay and let the main power into the system.

This red wire (yellow harness) is not prone to noise.

[m.s4]

So I ended up relocating the main power wire directly to the battery and the issue went away for a little bit. It's snowing here and the problem is back.

As soon as ESP activates the gauge flashes leaving the yellow light on when the rest of the lights go out. Does it less with ESP switched off but still does it if you whip around a turn and get wheelspin.

Seems that if I take out the ABS/ESP fuses the whole problem goes away, obviously leaving me without ESP/ABS.

My question now is, Is this power to the system related or is it Signal (IDC) related?

Also: New battery and did an alternator test and everything checks out fine.

Mark

[m.s4]

Update: unplugged a chinese made phone charge I had plugged in and the problem is a lot less consistent but still present.

[Richard L]

This is getting very interesting. I wonder if I send you another conrtroller it may not improve the situation.

We have a similar issue earlier with the gauge cable. I wonder if you can unplug and examine the wire ends, if any one of the stranded copper wire are close to touching each other occasionally.

From your description it appear to be a electrical noise problem. I like to send you an line noise suppressor and see if it helps. Ity is the first time we have this type of interference. Please pm me your address again.

[m.s4]

PM'd

I've checked the connections, all the non-used wires are separated and electrical taped.
All the other connections are soldered.

Thanks,
Mark

[m.s4]

Tried a new MAF today, still does it. It wil occasionally cut out at high rpms so I was trying to rul that out.

This indicates a loss of power to the aquamist, correct? Or should I be looking for something on my vehicle that is causing fuel cut and messing with IDC signal?

[Richard L]

I wonder if you can wiring the red wire of the grey connector directly to the igniton key switch (run of pre-crank position). Make sure it has a full 12V.

This inteference is so strange.

Is the s4 a FSi (direct injection system)? I think it is just a conventional injection system.