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Oil level sensor - "sensor" nagging problem!

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Old 01-16-2011, 09:31 AM
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Is it possible that the oil level sensor has a resistor in it, that reduces the voltage in service, so that if the full red/green voltage is "jumpered" to the grey/yellow line, it blows the fuse? But, if it is a lowered voltage due to a resistor, it may positively satisfy the sensor requirments? I contacted the sensor manufacturer, but they would not supply any technical info for it.

Does the Bently manual (or any another) have any more specific details on voltage levels required to positively satisfy or mimic the sensor performance?

Thanks again for any possible assistance or suggestions.
Also, feel free to e-mail me directly at lukcoolhnd@aol.com if you have any interest in helping to prevent my insanity...
Old 01-16-2011, 10:16 AM
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Originally Posted by lukcoolhnd
I have a 2002 A8 that has been great except for one nagging issue - I cannot get rid of the "oil sensor" error light! I have now replaced the sensor two times (the orginal error was a low level warning), and have spent numerous hours trying to check wiring, etc. to determine and correct the cause. I am temporarily able to reset the error by connecting two of the wires, but the error occurs again in approximately one minute. Does anyone have a wiring diagram, or any experience with this issue?

Here is what I have found thus far - it is a three wire sensor mounted on the bottom of the oil resevoir.
red/green wire - 12V input (actually reads about 10.5V)
red - ground wire
grey - return wire for 12V signal?

When I unplug/disconnect the senor completely, I get the "oil sensor" error message; when I plug it in, I still get the same error.
If I briefly connect the red/green to the gray wire, the error is cleared for about 1 minute. I have not been able to find (through trial and error) any method to jumper wires together, or to ground out any combinations to keep the error away.

Does anyone know a way to completely bypass the sensor? If I could do this, I might be closer to finding the root cause. I have contacted the sensor manufacturer, and they would not provide any electical schematics or design info.

The only reference I keep seeing on the internet is "wiring damage by rodents" - I have not seen any indication of this, and unless I can get connection information for the sensor wiring (where it connects into the main electical box), I cannot verify wire continuity to eliminate this scenario.

Audi "stealer" has recommended replacing the sensor (yet again), and then will proceed to replace the wiring harness.

I am not interested in spending $500 to start, and who knows how much from there - at this point it is just a ridiculously annoying riddle I am determined to solve! Any help would be greatly appreciated...

Thanks in advance for any thoughts, advise or technical info.
Red/green (terminal 3 on the sensor) is the level signal going to the instrument cluster.
Terminal 2 should be brown ground wire not red. Red is never ground on a german car.
Terminal 1 should be grey/yellow power from the injectors. I would try to connect a switched 12V here. I don't know why they used the injector wiring harness in that year. My 01' S8 has a switched power from a fuse.
Old 01-17-2011, 04:46 AM
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I did check the fuses several times, but after your suggestion, I checked all of the fuses in the passenger footwell fusebox - paying particular attention to the blue section. Surprise, surprise, I did find a 5A fuse that was blown (I had checked it visually several times, but until I checked it with a continuity meter, I didn't see it was blown).

I did also run a parallel ground wire, just to be sure.

My drive today was without any "sensor" error! Thanks for all of the help. I still don't know what caused the original problem, but I am much better equipped to diagnose it if it happens again - I'm hoping to never see it again!

Regards,
Luk
Old 01-17-2011, 07:15 AM
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Good deal! Fuse may have blown durin the first repair or during testing...glad you got worked out, though.

P.S. There should be a guide of fuse funtions on the fuse panel cover.
Old 04-18-2011, 08:42 PM
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Hi,

I just started having this problem with my A6 and I've run across this resolution: Replace the sensor unit with one bought from Audi. Someone stated that they had two after-market sensors and the Oil Sensor light kept coming on. Once replacing with a genuine sensor, the light behaved.
I think mine cam on because my oil level was low (yeah, my bad) - I added about 3/4 of a quart and I'm still getting the light, but the dip sick looks good. Maybe once it's tripped it needs to be replaced.
Old 10-25-2013, 09:52 AM
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Originally Posted by lukcoolhnd
I have a 2002 A8 that has been great except for one nagging issue - I cannot get rid of the "oil sensor" error light! I have now replaced the sensor two times (the orginal error was a low level warning), and have spent numerous hours trying to check wiring, etc. to determine and correct the cause. I am temporarily able to reset the error by connecting two of the wires, but the error occurs again in approximately one minute. Does anyone have a wiring diagram, or any experience with this issue?

Here is what I have found thus far - it is a three wire sensor mounted on the bottom of the oil resevoir.
red/green wire - 12V input (actually reads about 10.5V)
red - ground wire
grey - return wire for 12V signal?

When I unplug/disconnect the senor completely, I get the "oil sensor" error message; when I plug it in, I still get the same error.
If I briefly connect the red/green to the gray wire, the error is cleared for about 1 minute. I have not been able to find (through trial and error) any method to jumper wires together, or to ground out any combinations to keep the error away.

Does anyone know a way to completely bypass the sensor? If I could do this, I might be closer to finding the root cause. I have contacted the sensor manufacturer, and they would not provide any electical schematics or design info.

The only reference I keep seeing on the internet is "wiring damage by rodents" - I have not seen any indication of this, and unless I can get connection information for the sensor wiring (where it connects into the main electical box), I cannot verify wire continuity to eliminate this scenario.

Audi "stealer" has recommended replacing the sensor (yet again), and then will proceed to replace the wiring harness.

I am not interested in spending $500 to start, and who knows how much from there - at this point it is just a ridiculously annoying riddle I am determined to solve! Any help would be greatly appreciated...

Thanks in advance for any thoughts, advise or technical info.
I am in the same boat with mine. have done everything you have. its seems to go away as soon as I bridge the wires or put a resister in but comes back again when I put I back in gear again.
have you bridged the two wires together and earth the spare wire at the same time?
Old 10-26-2013, 11:32 AM
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found a code
00562 - Sensor for Oil Level/Temperature (G266)
30-10 - Open or Short to Plus - Intermittent
been told the bonnet sensor can trigger the yellow oil light so I cleaned the sensor and rewired it and guess what. I still shows code 00562 after clearing.
Old 10-26-2013, 02:28 PM
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Originally Posted by nickid
found a code
00562 - Sensor for Oil Level/Temperature (G266)
30-10 - Open or Short to Plus - Intermittent
been told the bonnet sensor can trigger the yellow oil light so I cleaned the sensor and rewired it and guess what. I still shows code 00562 after clearing.
That's the sensor attached to the bottom of your oil pan...it senses oil level by temp on a probe inside the pan, not a float sensor like a fuel level sensor.

If the wiring is OK, the sensor needs to be replaced.
Old 10-26-2013, 06:40 PM
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Originally Posted by nickid
have you bridged the two wires together and earth the spare wire at the same time?
Originally Posted by nickid
found a code
30-10 - Open or Short to Plus - Intermittent
Related possibly?
Old 10-27-2013, 04:50 AM
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Originally Posted by nickid
found a code
00562 - Sensor for Oil Level/Temperature (G266)
30-10 - Open or Short to Plus - Intermittent
been told the bonnet sensor can trigger the yellow oil light so I cleaned the sensor and rewired it and guess what. I still shows code 00562 after clearing.
The oil level (thermal sensor) sensor is not an on/off switch like other "sensors"....it reads the oil temp at the upper end of the probe, then sends a measured (resistance/partial ground) reading which is "translated" by the instrument cluster processor.

The sensor is shown as an electronic module on wiring diagrams...not a switch...so it can't be fooled or tested by shorting the wires together.

If oil is anywhere near full and the sensor triggers a code or warning, that's the test...it's bad.


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