94 corolla check engine light

I have a 1.6 that had the check engine light go on briefly on a short trip home. How do you access the codes. The O2 sensor has 150 K on it. I am figuring that is what it is, but would like to be sure. Thanks

I have a '95 (1.6L/4AFE), but the proceduire should be similar:

The DLC is in the engine compartment on the battery side, next to the fuse/relay box -- it has a cover that can be opened revealing a multiport jack -- the inside of the cover has a port map...

Using a jumper wire, connect TE1 to E1 -- then go in the car and turn the key to "on" -- the check engine lamp will quickly flash -- if there are no codes stored the lamp will contunie flashing every 1/2/sec.

Codes are two digits [flashes] seperated by a short pause -- codes are seperated from each other by a longer pause and they will be repeated.

I have the code book, so If you get any codes I can give you the text for them -- The Chilton's manual fir the Corolla has them, and you may be able to find them online.

Start the engine in this mode and you can interrogate the 02 sensor (actually the closed-loop operation): You need an analog DC voltmeter (digital will work, but it may be too fast), set to something more than 5v.

Leave the test jumper in place... Find the Vf(1) terminal and connect the voltmeter (+) to that, and the (-) to the E1 (ground) -- the engine should be running (the ignition timing in this mode will be retarded, so it may run rough) -- The throttle must be off-idle and running at about 1500 RPM -- the voltmeter should begin switching between 0v and 5v about every second when the sensor and the feedback is ok.

You can also check the O2 sensor(s) output(s) directly at the DLC -- You can remove the jumper or not for this -- The labeling may be different, but they are labeled Ox1/2 or Oxy1/2 ... voltmeter range around 1-5v -- (+) to Ox, and (-) to E1 -- if the sensors are giving any output, the reading should be 0-1v, switching across 0.5v about every second. -- when I do this, the rear (secondary) sensor does not switch and reads around .2v which I think is normal -- also, in '95 the secondary sensor does not throw codes.