996.1 OBC is confused about metric/imperial units

[Tobias Toft]

Hi everyone! I have a strange issue with my OBC that I haven't seen mentioned anywhere else on the various forums:

 

The OBC on my 2000 996 C2 is showing everything in mph (as it should, being a US car), but the actual numeric values are interpreted as (or rather, not converted from) km/h. In other words, if I'm going 60 mph on the highway and reset the average speed display or set the speed gong via the OBC stalk, they'll be set to 96 MPH (which is the corresponding numeric value in km/h). The temperature display, however, is showing the temperature correctly in Fahrenheit. Has anyone seen this before?

 

It should be mentioned that I activated the OBC myself with a Durametric cable after installing a new 4-stalk unit. The stalk works fine for navigating the OBC so I don't think it's a wiring issue, it seems more like a software configuration issue. Did I miss a setting somewhere in the Durametric interface when I activated the OBC?

 

So far I've tried to switch the mph/kmh units in the gauge cluster back and forth but it doesn't affect the OBC. I've also tried resetting it by removing the battery, also to no effect. 🤔

[Tobias Toft]

Apologies, I have to correct myself: 

I went for a drive last night and realized that my OBC temperature readout is in fact in Celsius. So, everything is read out in metric numbers but the labels in the LCD display are in imperial units (MPG/MPH) except for temperature, which is shown with a ℃. My current hypothesis is that my OBC firmware is configured as a non-US unit but the actual gauge cluster hardware is US spec. Does this seem like something that could be fixed by someone with the proper Porsche diagnostic tools?

 

Sorry if this is confusing — I'll post some photos soon!

[akk65]

As far as I know units in OBC are hard coded to gauge cluster, and they can’t changed. So I doubt that there is possible some hassle with activation, because readings are wrong. I have also retrofitted my OBC, and all working fine, only inconvience is that average consumption is displayed as ”km per litre” rather than normal (in europe) ”litres per 100 km” 

[987_RDC]

Yep looked around. You need to move to the UK now

Edited June 29, 2021 by 987_RDC

[Tobias Toft]

Here's an animated gif of me cycling through the different screens in the OBC. Notice the speed gong screen showing 125 MPH, I set that when I was going 77 MPH. FWIW, the digital speedometer shows the correct speed when driving, so the conversion issue seems to be isolated to the OBC readout itself. Strange...

[Loren]

I have done the OBC update on more than a dozen cars...

Either the PST2 (or PIWIS) setting were done wrong (wrong car order type, etc.) or someone installed the wrong used cluster.

 

Are you in Northern California or Southern?

[Tobias Toft]

Thanks Loren! Both sound like very plausible explanations (as far as I know the cluster is original to the car, but I could be wrong). I'm in the Bay Area.

[Loren]

3 hours ago, Tobias Toft said:

Thanks Loren! Both sound like very plausible explanations (as far as I know the cluster is original to the car, but I could be wrong). I'm in the Bay Area.

 

If you are ever over this way I can hook up my PST2 and the settings.

[Tobias Toft]

Amazing, thanks Loren! Sounds like a good excuse to go on a longer drive 😉

[987_RDC]

Loren can a PIWIS One or II do the settings? I have access in San Jose.

[Loren]

Yes, any Porsche diagnostic tool should work as they are all backward compatible.

[Tobias Toft]

Wanted to close the loop on this one, in case other people have this issue.

 

I managed to get the car hooked up to a PIWIS II tester today and it turned out my instrument cluster was configured as an RoW cluster despite it being in imperial units and sold in the US. I suspect that since the car was originally sold without OBC there was no reason to change the region coding on it when it was manufactured. A quick configuration change to 'US' with the PIWIS II (it had to be done in Development mode) fixed the issue, and now my OBC is much more usable.

Edited March 11, 2022 by Tobias Toft

[987_RDC]

Cool good update. PIWIS in E mode guessing.

[Tobias Toft]

Correct!

[rabit]

Apologies for replying to an old thread, but for anyone else ending up here via google, try this:

    - twist and hold the clock adjustment counter-clockwise for a few seconds

This should switch between imperial and metric units on the DRO.