CAS: D904/not present - CAS K-CAN line fault

[mate.118i]

Hi guys!

i was investigating an OBDII error initially on my BMW e88 118i N43 engine UM12 type car after engine light going and coming. As the P2096 didnt mean much i replaced the pre catalytic O2 sensor but no luck, then got a foxwell NT510 bmw diagnostic tool. As a start i had reset all codes yesterday morning and by now, i got the below errors:

CAS:
D904/not present - CAS K-CAN line fault

DME:
2EF7/not present - DME Map thermostat activation
30C1/not present - DME Engine-oil pressure control, static
2AF4/not present - DME Nitrogen-oxide sensor, electric
2AF2/not present - DME Nitrogen-oxide sensor, lambda linear
2AF6/not present - DME Nitrogen-oxide sensor, signal
2C31/not present - Oxygen sensor emissions control

So its 2x codes less compared to how it was before the reset, but maybe they’ll appear anyway after sometime probably.
Would you say that there’s an issue with the Nox sensor? And what’s the K-CAN line fault? Could it it be a wire that causes the whole issue?

looking forward for your opinion

[dworthy]

Run down the bus and see if it is cut/rubbed/burnt somewhere.

I think this is the correct wiring diagram for your car: https://www.newtis.info/tisv2/a/en/e...x15006/oKqRbTF

As for the other DME codes, check your fuses first, then test each item using the website I supplied.

[mate.118i]

Run down the bus and see if it is cut/rubbed/burnt somewhere.

I think this is the correct wiring diagram for your car: https://www.newtis.info/tisv2/a/en/e...x15006/oKqRbTF

As for the other DME codes, check your fuses first, then test each item using the website I supplied.

Wow i didn’t even know about this website.
But how did you end up suggesting looking at x15006-x15006 loop? I mean i understand that since the error has CAS in it would imply Car Access System but how would you know where to look?
Sorry if my questions might be silly, but never did car electrical / electronics related works on a car.

[dworthy]

Not silly by any means. Yes, check between the connectors to ensure you have a good wire running, you will need a multi-meter. Do a google search on "Continuity Testing" and that will tell you if the wires are okay. Next you will need to use an oscilloscope to look for signal, but for that I think you will need a shop.

[shadowpuck]

mate - i think the clue was in the trouble code description "CAS K-CAN line fault"

that right there tells us there's some issue with one of the networks in the car. this is a network by which many of the modules in the car communicate.

[328 Power 04]

Also, cas modules simply fail sometimes.

[mate.118i]

so gents, i have traced this to be the passenger occupancy sensor.
lucky i got the part at a local shop, spent my whole Saturday on it,
time to look at the other issues :/

[bmwdirtracer]

Yeah, um...the occupancy sensor isn't related to the codes above.

Start by replacing the thermostat; that's a given.Likely you've got a bad NOx sensor, too. I'd be worried about that oil pressure code, as that one can kill the engine dead.

[mate.118i]

Yeah, um...the occupancy sensor isn't related to the codes above.

Start by replacing the thermostat; that's a given.Likely you've got a bad NOx sensor, too. I'd be worried about that oil pressure code, as that one can kill the engine dead.

Well the occupancy sensor was the reason of the K-LINE error code (which i tought that it could have something to do with the other problems - for example issue with the bus down to DME/DTE). After replacing the sensor the K-LINE issue went away forever

NOx sensor on its way!

And i’m also worrying about the oil pressure warning mainly because i did hear rattling sound a few time during engine startup (reminded me a steam engined train) but inwas assured more than once by the mechanic that i shouldn’t pay attention as it only happens during warmup and it could be a pressurizer. Nevertheless i don’t enjoy the fact either that i had to buy a diagnostic tool and find out myself the the oil pressure and thermostat errors are almost permanent (they come back within minutes of erasing them)

I’ll post an update once NOx sensor replaced. I’ll request an oil pressure test and a smoke test and take it from there

[bmwdirtracer]

I'm very glad you've found and fixed your culprit, but I'd have to consider some part of the initial fault code for the K-CAN to be incorrect wording. After all, while the passenger seat occupancy sensor reports to the MRS (Multiple Restraint System), which is certainly on the K-can bus, that's really not a "line fault" on the K-can at the CAS. Ah well, all that matters is that you got a capable scanner, which pointed in the CORRECT direction.

You should replace that thermostat. Be aware that an engine running hot, because of, say, a thermostat that's not opening on time, will produce more NOx. AND, perhaps cause the engine to overheat, costing a LOT of money.

If you have ISTA, BMW's own diagnostic system, it can do guided test plans for your codes, which might lead you exactly to the cause of the oil pressure and NOx codes