69 DME: Signal, engine temperature, implausible

[Slideways]

Yes and I'm getting a reading of 86 while running, but not sure if celsius or fahrenheit.

Celsius

I did have a new genuine BMW temp sensor (under the manifold) go bad after 20k miles. The temp gauge would randomly fall all the way to the first dot while cruising on the highway.

[Halftim3]

Yes and I'm getting a reading of 86 while running, but not sure if celsius or fahrenheit.

[Slideways]

Starting to monitor the digital display in the hidden menu, is this in celsius or fahrenheit?
George Hill maybe it could be the seal inside the thermostat housing as you mentioned in another thread. Which i guess is now NLA

Has the thermostat ever been replaced on this car?

[George Hill]

Starting to monitor the digital display in the hidden menu, is this in celsius or fahrenheit?
George Hill maybe it could be the seal inside the thermostat housing as you mentioned in another thread. Which i guess is now NLA

To diagnose this you are going to need a scan tool that can read data out of the DME independently of the cluster.

[Halftim3]

Starting to monitor the digital display in the hidden menu, is this in celsius or fahrenheit?
George Hill maybe it could be the seal inside the thermostat housing as you mentioned in another thread. Which i guess is now NLA

[George Hill]

From my experience with this fault...

The fault is set because the DME is comparing the engine temp and radiator outlet temp. The code is present when it thinks those two temps don't make sense. What its logic is for that I'm not 100% sure, but I think it has to do an example like this... If the ambient temp is 30*, the engine temp is 60*c and the rad outlet is 50* then it assumes one of the coolant temps is incorrect because the radiator shouldn't be that how with the engine temp that cold. Since the DME can't monitor the thermostat itself it can't set a fault for a bad tstat like an M54 can. So a bad temp sensor or thermostat is often the cause.

*Usually I see this during the warm up phase but it can happen anytime. Maybe the DME is taking into account its oil temp calculations too?

Either way, my process for addressing this is I replace the thermostat and the temp sensor, with the thermostat out you can just barely access the temp sensor so its just a smidge more labor and the price of the part.

If that didn't fix it there isn't a consistent "next" step, it seems like all the cars are relatively different at that point as to the cure.

[ATB88]

I had a 2 year stretch where I was getting this code too. I replaced the coolant temp sensor under the airbox, and then the thermostat. Fan clutch is relatively fresh. Code would just randomly appear once every six months. Eventually it just stopped ¯\_(ツ)_/¯ Haven't seen it in at least 18 months.

Back when this was happening I did a little research and found a couple similar reports on other forums. I bet it's not your thermostat.

If you ever get any insight into what causes this i'd love to know!

[sapote]

6leared the code, but the code comes back.

What temp displays on the gauge or the hidden menu? If it's much lower than 85C then the code means bad Tstat.

[Halftim3]

Ok I have replaced the sensor in the lower radiator hose then I cleared the shadow code, but this code came back still. So far I have replaced the 2 sensors (under intake manifold and lower rad hose). I also replaced the fan clutch. I dont think i have an overheating issue, the needle stays in the center and sometimes fluctuates slightly to the left cool side. I do notice the coolant warms up slightly quicker than the oil just by looking at the gauges, guessing the thermostat maybe failing, but would this trigger the code or does that have a separate code?
What else could be triggering this shadow code?
Any advice appreciated, thanks.

[Slideways]

You gotta be quick as it will pour out rather than leak like the other sensor. The system bleeds itself as the coolant expansion tank is the highest point.

[Halftim3]

Alright, when I replace that lower sensor, it would likely leak, but would I need to bleed the system? Thanks.

[Slideways]

Coolant temp sensor in the lower rad hose

[Halftim3]

69 DME: Signal, engine temperature, implausible

This code keeps popping up, I have searched some threads and have replaced with a new ECT sensor under the intake manifold (part number 13621433076), cleared the code, but the code comes back.

Does anyone know what else it could be? Thanks.