Checking oxygen sensor on Corolla


Old 01-05-04, 09:35 PM
Thread Starter
Join Date: Feb 2003
Location: USA
Posts: 228
Checking oxygen sensor on Corolla

I have an 86 Corolla LE with 4AC engine. Tested the oxygen sensor via the service connector. The voltage swings between 0-4.2 v about once every second at 2500 rpm. Manual say it should swing between 0-7volts. Does the low voltage reading (4.2v) indicate a bad sensor?

Also, did they make the earlier oxygen sensors put out higher voltages? Seems like what I've read about most oxygen sensors, voltage readings are under 1 volt.
Sponsored Links
Old 01-06-04, 04:01 AM
Desi501's Avatar
Join Date: Oct 2003
Location: Boynton Beach Florida
Posts: 2,207
That's correct. O/2's rarely peak over 1 volt. They generally jump between .100 and .900. If you are getting a reading over 1 volt, then your are either on the wrong wire or there is a problem. If it has more than 2 wires, it has a 12 volt heater and could be bleeding over although I don't remember an older Toyota having a heater.
Old 01-06-04, 06:09 AM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
The reading you are getting is correct. It is reading the 0-7 volts from a Feedback computer. At the sensor it would be 0-1.0 volt like Desi stated.

So therfore you sensor is reading lean. Hold you hand slightly over the top of the carb to richen and see if the sensor will respond by outputting a higher voltage. If not the sensor is NG.
Old 01-08-04, 12:58 AM
Thread Starter
Join Date: Feb 2003
Location: USA
Posts: 228
I repeated the test on the oxygen sensor with my hand held slightly over the carb and voltage did not go any higher. I'll be replacing that sensor with a new one.

Thanks for the replies.
Old 01-09-04, 11:13 AM
Visiting Guest
Posts: n/a
What is the problem with the vehicle? The O2 sounds ok, you may be replacing a good O2!

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes