1990 olds delta 88 trouble codes

i just ran codes on my 1990 olds delta 88 and it always gave me a code 23...which is the mat sensor. well today i ran codes again and i got 23 as well as 26...26 is some kind of quad thing. i have maintnence manual for this car but i can not figure out why both codes are coming up. i think it might be the ECM. any suggestions?

The 26 is a quad driver code this driver operates high load solenoids, egr solenoid , tcc solenoids and such, the fault refers to overloading one of them, so you need to isolate the circuits to find which one is setting the code, google this code lots of info there. Do a full scan and check the mat sensor readings or just see if is disconnected to start out.

the mat sensor is fine. i have exactly 5 volts coming from the connector. and the senser is reading the right resistance according to temp. so i have no idea whats setting that off. i'll check in on that quad driver