check engine light 1990 300se calif
 

CEL on .02 sensor was replaced 10k ago what should I do?newbe

Welcome to the forum. As always when CEL is on, the place to start is by pulling codes from the diagnostic connector, located near the battery and inner firewall on right side. CA versions have a red LED which blinks out the trouble codes for you. Then, look up the codes and you'll have an idea of what's triggering the CEL. Search on CEL or trouble codes; tons of info.

well it can be just about anything from a misfire to a low voltage reading,or most commonly low voltage from the oxygen sensor or 02 sensor,its located pre catalytic converter and it mixes the air fuel ratio after sensing the exhaust fume measurements of o2 and co2

checked led flashs
 

it flashed 17 times=02 sensor? car runs fine.smells a little rich at idle.like i said erler about 10 or 15k 02 sensor was replaced was around 380 by local shop.maybe he put on one of the cheap ones.have to smog it soon.last time they had a hard time getting it to pass really had to heat up the car before it past smog.car has 160k on it not a daily driver sits in my garag most of the time
? how do I clear the light on dash.want to see if light come back

I think code 17 is an oxygen sensor, so you're probably right.

As for passing smog, is there any documentation of the valve seals being done? This is a common wear item with the M103 and can lead to increased oil consumption and higher emissions.

Disconnecting the battery for a bit will reset it.

yes
 

top end off car is good.oil consumption is normal.weird. sensor only lasted 15k
not much room to access sensor.under car above ex pipe.not shur where wire lead go's to? think its under pass/side floor mat .blue wire