Engine instrument communication loss mid flight

Does anyone have any idea why I would see a “engine instruments sensor communication loss” on my MFD? The stand by analog instrument gauges worked just fine, so I am thinking it could be the module. How expensive are those?

The analog instruments are primary on your aircraft since in this case, there is a SIU (Sensor Interface Unit) translates the info onto the MFD. Part number is 14843-002

What happened right before the engine data was lost? Did you get a jump start through the power port? This is a great way to destroy the SIU.

If the engine data went out during a flight and later comes back on when on the ground, this is typically a poor connection (of a pin) in the cable between the SIU and the MFD. The solution is to spray a contact enhancer on those pins and re-insert them several times. De-Ox-It or Stabilant is a contact enhancer.

Very , like $4K expensive from Cirrus unless you can find a used and working one on ebay cheaper. Is the engine instrument data hard-dead or does it stop working at some point after power-up? Many times there are intermittent grounding or switch positions that need to be addressed. Lots of threads on this in the members section. Bottom line is that you might have a dead SIU, or maybe one that could be revived with some trouble-shooting.


Does this company still service the Moritz DAUs and SIUs?

Radiant Power (DAU & SIU) Repairs
7135 16th St E #101, Sarasota, FL 34243
(941) 739-3200 EXT# 268
Mike Paulsen mpaulsen@rpcaero.com

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I had Engine Sensor Unit not communicating error couple of times in past year. I recycled Engine Instruments circuit breaker and indications comeback. Haven’t happened in long time.


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Ok. So nothing unusual.We were going through some moderate turbulence. But before that, maybe an hour or so earlier, I had tried to charge my iPhone 14 through the USB data port on the MFD, but it would not charge. so I unplugged it quickly. Hoping that did not create the issue.


I don’t know if related but the USB ports on the MFDs are for data thumb drives only

They are not for charging

Got it. but would it have anything to do with the SIU going down?

The oat probe needs to have the probe connector shield ground checked often…

Its a static issue in the electrical sensor system.

Here is the service bulletin that fixes this issue.

SB2X-34-08R1.pdf (220.7 KB)

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The SIU probably did not go down. What happened is the MFD’s internal power supply got loaded down by hooking up the phone charger to the USB port. This same power supply is used on the MFD serial port.

So you killed the MFD’s communication channel when you did that. Hopefully not permanently.

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Thanks Paul. Hoping that’s it. My shop did not have power for the last few days due to the storms and they will look at it on Monday. Fingers crossed.