check engine light is on on 2002 Suzuki Aerio

Had the car hooked up to 2 different handheld computers,1 read 02 sensor and the other cat. converter. Then took the car to a machanic and hooked up to the big machine.He told me that after changing the Downstream sensor,the problem should be resolved??? Where is the Downstream sensor located?And what kind should I purchase? the universal,alternate,etc.?

Asked by for the 2002 Suzuki Aerio
1 answer
The downstream sensor is the last one located on the exhaust pipe, check the exhaust manifold in front of the engine there should be an oxygen sensor that would be 1/1 or upstream the sensor after that would be 1/2 downstream. best to buy from dealer, jobbers seem to not last as long.