More information on my issue.
I have been having an error where no DTCs are set but when monitoring my I930 signals when driving the PID Damper Firm error =YES. All shocks are firm. Level is fine. Compressor works as it should. I decided to OHM out the switching solenoids on each shock. ( the solenoids that control soft and firm) Testing the front ones a measure 5.4 ohms on both front shock. The rear ones measure 2.4 ohms on both. Is this correct? I thought they should all measure 5.4 ohms.

 

New news to me, and 'just in time'. Hope to pull one if not both rears tomorrow. Will check both DC resistance in Ohms, annnnnd .. inductance in fractional Henrys ......once I have access in the boot.

Not that it has the same utility for my needs, given my replacement struts have no solenod modulated valving.

All I need the info for is to select appropriate "cheater shunt" resistance (and Wattage..) values to prevent error messages arising.

 

That would sure be nice to know since no one seems to know the real answer.

 

The OEM Bilstein will be whatever it is, DC Ohms or AC/Pulsed Inductance.
I'll post both values once I'm into the wiring.

Resistors meant to be here Saturday should arrive Monday evening. Not planning to cut into the wiring until I'm ready to connect those.

That said, I THINK both resistance and inductance annnnnnnd 'workable' values for 'cheater' resistors as well... HAVE already been posted?

I've ordered five each in 15 Ohm and another five in 20 Ohm, 'will adjust' if those aren't close enough.

 

Hi knowit,

I had a few minutes this evening so I measured a couple of air spring/dampers randomly selected from my collection.

The DC resistance of the front unit's ECATS solenoid is 5.3 ohms (Ω):




The inductance of the front unit's ECATS solenoid is 13.1 millihenries (mH):




The DC resistance of the rear unit's ECATS solenoid is 5.3 ohms (Ω):




The inductance of the rear unit's ECATS solenoid is 12.8 millihenries (mH):




I connected to the solenoids using an OE harness connector cut off of an X350 that I converted to Arnott coil suspension:




When you measured the resistance of your rear units, were they connected to the vehicle harness? If so, there could be some parallel resistance in the circuit that is causing your measurements to be low.

Cheers,

Don

 

Thanks so much for this info Don. Much appreciated. When I measure the resistance I did it at the connector where all the ecat solenoids plug into the ASM. The connector was disconnected from the ASM to take the circuit out of the loop. Possibly somehow I am reading through both rear ecat solenoids at the same time. That would explain the 50% resistance reading. Going to measure right at the strut next time. For all intents and purposes my suspension seems to be operating correctly except for the Damper firm error=yes. I sure would love to know what causes that error.

 

OK, so quick update on my issue. External temps DOES make a difference it seems. It's like as if some electronics somewhere needs to warm up to give correct readings. 36c external temps now = no firmness fault! Anything below 30 and it needs to warm up before it softens up! So I'm suspecting recently swapped front right shock may be faulty OR the front height sensor I bent when doing the first shock (forgot to take it apart). May have moved some of the internals enough for heat expansion to "fix" it. I'm guessing it's just a carbon track and arm type deal. I have a new OEM one on the way so we will see.

New development though. My right rear shock has started to hiss over bumps. It's not bottoming out and compressor refills it but clearly it has a leak so this may be the culprit!! I have yet another Miessler unit on order and will swap it out next week hopefully. Also likely to be the cause of my overnight sagging and maybe the firmness error. I will not install the new sensor which hasn't arrived anyway, at the same time as the shock, just in case I fix the fault, I'll want to know what fixed it!!

I will report back!