I'm trying to confirm DTC diagnosis on a 1992 400E. Driving the car up and a 1/4 mile section of road I got the ASR light on 3 times in about 10 minutes (from initial start so engine was cold initally and never got real hot). Codes were - pin 6 code 30 and pin 7 code 3 (38 pin X11/4) all codes could be reset. I replaced the FI harness (which was all cracked) this was the first drive since replacing the harness. Previous codes (prior to FI harness replacement) were;

4 - none
6 - 13, 17, 30
7 - 3, 5, 14
8 - 6, 9, 17
16 - none
17 - none
30 - 3, 8
No Idea when the last time codes were read or reset from the previous owner.

On reading the codes there was a high pitched whine in the engine compartment with the ignition in the on position (climate control off). I believe it was from the area of the ETA but I cant be certain. I'll remove the air cleaner tonight and see if I can isolate the noise. A coworkers 92 400E makes no noise with the ignition in the on position. All 3 times it went into limp home mode I was stationary with my foot on the brake. I was hoping for a brake switch code but thats not what it looks like.

From when I replaced the FI harness I noted that the bottom of the throtle plate was dirty. Could a build up of stuff in this location cause this symptom? I figure I'll pull the air mass sensor and then clean the accessable mechanical parts of the throttle actuator.

I want to do a thorough diagnosis befor throwing money at parts. Plus I'm waiting till it eventually gets to 60deg here so I can fix the small rust spots befor I put the car on the road. Taking my time to fully sort it out is OK, I have other cars to drive in the meantime.

Thanks for any help
Paul
84 300SD
92 400E

Pulled the air intake and the noise is definitely from the area of the ETA! Checked codes again just to make sure that they are not active (stayed cleared, and they were clear.

The butterfly (disk) area of the ETA is really dirty. Figured it may not get fully closed. Pressed gass pedal and the noise went away!

I'm hoping I'm dealing with an issue of dirt. Should I remove ETA and clean out of the car? Should I try to clean in place with the hot wire mass flow sensor removed? Has anyone used throttle body cleaner through the vent hose with the engine running (as per the throttle body cleaner directions)?

Paul