I have a 97 Dakota V6 4x4 auto bought it about 2 months ago and have been going through it, tune up, brakes, belts, hoses, oil & filter, battery, etc., I have a check engine light that shows the P0138 code, Could someone shed some light, it's supposed to mean the following: P0138 (M) 1/2 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normal operating range. Does it simply mean that the downstream 02 sensor needs to be replaced? Any input here would be appreciated, Thanks, Lj

 

I can't say you are definatly correct, but from what you state, that is what I interpurt it as the downstream O2 is bad causing short.