Wow yesterday I dropped the GF off at the Mercedes Dealership to pick up the 500 SL for service and drove up the hill towards home, decided to stop and get gas and the BKO started running really rough, stalled and wouldn't budge when I restarted putting it in drive, it just wouldn't go, I was freaking out thinking is the rebuilt AOD tranny taking a dump, I just serviced it with filter and fluid not long ago ....then managed to pull in for gas.
I looked under the hood and noticed some mystery fluid spayed up on the underside of the hood just above the brake booster and all over the booster but I couldn't figure out where it came from, looked over everything with a flashlight but didn't find anything leaking.
It restarted no problem after putting in $25.00 of gas which was like a fart in a wind storm....lol lol and then it did it again, same symptoms as I'm pulling out, restarted and barely managed to keep it running but got it home, stalled going thru the security gate, got it in the driiveway.
So popped the hood and pulled codes immediately and got:
KOEO 54 -ACT sensor signal is greater than the Self-Test maximum of 4.6 volts
KOEO - 31 - PFE or EVP circuit has intermittently failed below minimum voltage of 0.24volts.
KOER - 24 - ACT sensor out of self test range 0.3 to 3.7 volts.
KOER - 41 - HEGO sensor circuit indicates system lean (right side).
No HEGO switching detected always lean (right side).
I mean this was out of the blue, the BKO has been running like a swiss watch, though recently I did have an issue, code: 31 EVP out of range but this turned out to be my #1 & #5 spark plug wires, #1 the clip inside was out of shape not snapping on the plug real tight so I replaced it with a spare and #5 boot was split on the bottom cross arcing and that clip was out of shape so I recrimped it and swapped out the EVP sensor and the code: 31 went away and it's been running smooth as silk since.
So I have a blood disorder and need to be mobile no matter what so I decided to replace the IAT sensor which IIRC has been on the BKO probably 7-8 years so for $16.99 it was time to replace it and I had swapped the EVP with a spare which is probably the one that was on the BKO 9 years ago so I bought a new one and swapped that as well.
Took it around the block several times for road test now it's runnig smooth as silk again.....so I'll keep a close watch and check codes again to be sure.....
All this after replacing a radiator cap, themostat, fan clutch and temp guage sending unit the week before because my dash temp gauge needle is off, it runs up towards hot NORMA/L and fluctuates a bit and I haven't figured that out yet, it's not over heating or running hot so it's got to be a voltage issue....IDK.....PITA..
Just on the odd chance I checked the master cylinder fluid and it looked a bit low in the reservoir so I topped it off and cleaned everything....weird.