It's not an easy problem really, since the oil level is going to bounces around a lot when driving. That's probably why the modern Porsche's are do bad at it, sometimes making you wait a day or three before giving you a decent reading.
If the dip stick reads full when the motor is off, does it still read full when the motor is running? I'd think the circulating oil would lower the level in the pan by some amount. Maybe reving froths it back up? Uphill, downhill, bumps, cornering -- all opportunities for false low levels. I think it's going to be tough to come up with a warning light that really works when you are driving around using nothing but an on/off sensor like that. I'm sure that's why the factory system really only checks at start up -- when conditions are calm and predictable... I'm sure you could do that with minimal electronics. Turn on car, delay 1 second, check sensor, if it's low for more an 1 second, turn on light and keep it on until ignition is turned off... Or tap into the TPS and and only turn on the light if the TPS is close (at idle) AND the sensor shows low for more than X seconds. That still might not work on hills and such, but might be closer to what you are after...
Low oil level indicator function
-
Tom
- Site Admin
- Posts: 8947
- Joined: Fri Jun 25, 2021 2:04 pm
- Location: Silicon Valley, CA
- Has thanked: 936 times
- Been thanked: 4013 times
- Contact:
Looking at this further, I found there is a circuit board located inside the cluster which provides the oil level function. The connectors we see on the cluster are actually the back side of the connections to it. The original version had some issues in some 968s, and it was upgraded to part number 944 641 959 02. Details in the technical bulletin group 9, number 9402.
I have to agree with Tom that trying to make sense of the signal coming from the sensor while operating, especially in a racing environment with high lateral, acceleration, and braking loads would prove difficult at best.
I have to agree with Tom that trying to make sense of the signal coming from the sensor while operating, especially in a racing environment with high lateral, acceleration, and braking loads would prove difficult at best.
Do you know which tech bulletin doc it is in? I have all of the printed ones applicable to 944s. They usually list them by letter for the volume.944er wrote: Wed Sep 17, 2025 11:46 am Looking at this further, I found there is a circuit board located inside the cluster which provides the oil level function. The connectors we see on the cluster are actually the back side of the connections to it. The original version had some issues in some 968s, and it was upgraded to part number 944 641 959 02. Details in the technical bulletin group 9, number 9402.
I have to agree with Tom that trying to make sense of the signal coming from the sensor while operating, especially in a racing environment with high lateral, acceleration, and braking loads would prove difficult at best.
I did some digging in my parts and found this old housing and I can see the board.
I did not have time to look at this in depth. I may try to scavenge this to see if I can use it in the race car but it looks like it does not have the oil level connection.
I did not have time to look at this in depth. I may try to scavenge this to see if I can use it in the race car but it looks like it does not have the oil level connection.
- Add Pictures/Files
-
- Capture.JPG (75.69 KiB) Viewed 236 times
-
Tom
- Site Admin
- Posts: 8947
- Joined: Fri Jun 25, 2021 2:04 pm
- Location: Silicon Valley, CA
- Has thanked: 936 times
- Been thanked: 4013 times
- Contact:
Pretty sure they all have circuit boards in those locations. On cars with the oil level warning, it's just a different board (I believe). I have some old clusters I can check this weekend if not sooner.
Book K, page 111. The service bulletin indicates 968, for years 93 and 94, so may have been a supplier issue on the original boards during that period, but the older PETs indicate to use the revised board for replacement.AZMI951 wrote: Wed Sep 17, 2025 1:28 pm
Do you know which tech bulletin doc it is in? I have all of the printed ones applicable to 944s. They usually list them by letter for the volume.
In the 87 schematic, which is the the OP's car, they are not numbered sequentially. In the 88 schematic, they are renumbered in a sequential manner.AZMI951 wrote: Tue Sep 16, 2025 3:40 pm 944er, The circuitry up to pins 5 and 12 is very simple so something else must be going on to achieve the logic described in the owners manual. I also don't think the numbering of Additional Electric is correct, if you look at the schematics they are not labeled sequentially.
The board is powered off of fuse 18 going into pin 3 on the board/additional electric.
Board GND looks to be on pin 6 for year 87 or pin 7 on the 88 schematic.
Also attached is the TSB noted.
Board GND looks to be on pin 6 for year 87 or pin 7 on the 88 schematic.
Also attached is the TSB noted.
- Add Pictures/Files
-
- IMG_1324.JPG (3.75 MiB) Viewed 219 times