I know zip about codes, but I'll throw in my 2 cents anyway.
Arthur Dalton mentions that one code points to the -> air intake temp. sensor.
In a previous post(month or so ago), someone with a similar configuration(2.6/3.0-M103 I believe) had a check engine light that was brought on when they started the car with the air intake temp sensor unplugged. I believe this person was changing out an air filter and for whatever reason, started the car with air intake items removed. His vehicle threw a code that indicated this.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.