:they dont tell you anything ( specific). they only indicate a problem in that AREA. O2 sensor codes doesnt mean (necessarily) your o2's are bad, det sensor code doesnt mean det sensor is bad. Sensors are only part of the circuit.
From experience, you might do a simple resistance test ( with an ohm meter) on your det sensor/ if it's bad you can get by with a $1.00 resistor from radio shack. you may have a broken wire, loose connection etc.