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Service Engine Soon Light

I have a 1997 Ford Ranger with a V-6. The service engine soon light keeps coming on even though my mechanic has installed serveral new oxygen sensors. The computer is indicating this is the problem, but after putting a new one in, several days later the light comes on again. Anyone have any suggestions.

likely the sensor itself is not the fault, but the wiring itself. the connectors often have loose wires, connections, and sometimes the wire (where it is held with wire zip ties) gets pinched, and the wires short out there too.

sometimes just taking off the connectors and cleaning/replacing the crimp on terminals is a help.

Ditto to what Cappy said. What is the O2 sensor code?

A lean or rich O2 sensor code does NOT mean the sensor needs replaced.

Most of the time the O2 is just a messenger for problems elsewhere.

Dont shoot the messenger.

i told you last time,check the PCV hose.



you know alot about cars to pose a question like that.(my opinion)

Were the codes read again when the CEL came on after the oxygen sensors were replaced?

I dont know if this will help but we have a 2001 chevy silverado and there are times when the light turns on for no reason. In the trucks manual we found a kind of “code” to turn it off. on our truck we have to turn the switch on to where the radio turns on but not the truck itself, then we have to step on the gas pedel 3 times holding it down on the 3rd time. The service engine soon light turns on and off 3 times then stays off. Check your owners manual maybe yours has something like this. However this happens mostly when we’ve just changed the oil.

nybo brought up a good point.

are you having the codes read again? you CANT assume the codes are the same. each time you repair something you must erase the code, and when the light comes on you have to re read it. you cant just assume it is the same code each time the light comes on.

Are you sure this turned your “check engine” light out? This is the procedure for turning out the “change oil” light.Get your truck scaned for “history codes” it may indicate something you want to know.