High Ambient Temps and 1999 E300D is acting up...
 

Today here in Yuma, AZ it got to 119°F or 48°c for all you foreigners, and the car got a CEL for P0235 (boost sensor malfunction) and the car would surge with acceleration (in small increments, with little power) The A/C would cycle on and off and just blow hot air (may have been the surging engine power) and lastly the ASR/BAS light came on. I have the new brake switch but could this switch be at fault for all of this? The car had been sitting in the sun all day and internal temps were 135°f (55°c) mind you the car is black.....can it not survive the heat? I drove it again after it was parked in the garage and the sun is setting, it is only 110°f outside and it runs fine now with no lights........

Get the **** out of that hell hole.

Well I cleared the CEL by dropping a little MAF cleaner into the Boost sensor and also blowing out the sensor line. I used left over injector return line as the sense line, might be too small and the oil vapors from the PCV are clogging it up. Need to get a catch can put in there I suppose. I also changed out the brake switch, the old one was fully collapsed and had no spring pressure left so that explains the ASR/BAS light.

At those temps I would expect the ecu is struggling with the readings from the intake air temp sensor, ac must be on the limit hence off and on trying to cope.
Thats a touch hot 48c !!!!!

BOL +1

Yep, the ac is maxed out! I bleive the AC coolant temp cut off switch is set to 50-55°c hence it cycles on and off. Its easily that temp under the hood in direct sunlight. Looks like the Benz will always get the garage in the summer months...sadly it gets hotter

I live in Goodyear, Az so I feel you pain. Just wondering what you are seeing for coolant temperatures? Thanks

In stop and go traffic I sit at about 90-92°c but if I'm moving 85°c. I'm pretty sure I put in an 85°c thermostat not knowing 80 is what it should be. Even yesterday it was 113°f and it stayed below 92°c

Thanks for the info. I recently changed the thermostat and fan clutch but on the I-10 the temp does not come down to 80/85 while cursing. So maybe another thermostat is on order. Maybe the new one is not quite right. Thanks again.

This is actually true. Black (or dark colors) absorb radiant heat from the sun and thus have a higher surface temperature. The side-effect is higher heat radiated into the interior of the vehicle.

The same thing applies with dark vs. light colored interiors. Window tinting and a reflective sunshade for the windshield helps a LOT.