M62 engine.

Hooked the IID today after the oil change for no particular reason, just to check for codes if any.

I got the "Electric thermostat circuit fault" which I reset.

Ran the car to work an code reappeared. Cleared again and checked the plug and contacts which seem in perfect condition.
Code reappeared on the way home and persists...
Thermostat is newish, some 10 months old, BEHR 105C.
I'll follow the wiring towards the ECU box tomorrow.
The car drives just fine and throws no warnings.
Indy said this could be a bogus error but it wasn't there before so I need to investigate.

Can the thermostat heater element go bad that soon? Can I test it with a multimeter to see if there's any resistance? I guess could be whatever except infinite...Is there any fuse for it, perhaps?

Some graphs attached if anyone can make sense of and perhaps make some logical assumptions...

Thanks








Last edited by vs322 on 6th Nov 2021 6:03pm. Edited 1 time in total

Lots of info here, shows what a waste of time it is to keep it, does your engine no good at all...!!

https://www.fullfatrr.com/forum/topic39362.html Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thanks one more time, Pete. I'm aware of the mod and may in fact go for it eventually if this is proven to be the thermostat. I do prefer to keep my car in stock configuration but this mod indeed has its merits.

The ONLY reason for the stock excessive heat was to pass emissions, nothing else, BMW never ran the engine that hot...!! Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I've done the mod. I'd like to knoiw what resistance I need to connect to the wiring to emulate the heater element and thus get rid of the fault code. Ron B. VK2OTC
2003 L322 V8 Auto
2007 Yamaha XJR1300
Previous: 1983, 1986 RRC; 1995, 1996 P38A; 1995 Disco1; 1984 V8 County 110; Series IIA

Pleased to report that the issue has apparently been resolved. Disconnected the plug once again, soaked it in WD40 and gently pushed / bent inwards the metallic terminals on the plug to achieve a tighter fit. Squirted some more WD40 on the thermostat terminals as well.
The fault has not returned in two 40' full driving cycles under various traffic & load conditions.
Weather has been exceptionally damp over the past three or four days and the fatty stays outside so this could be the root cause...