Go Back   Club Lexus Forums > Lexus Model Forums > SC Models > SC 400/300 > Performance & Maintenance
Sign in using an external account
Register Forgot Password?

O2 sensor resistance (cold)

Thread Tools Search this Thread Display Modes
Old 07-26-14, 05:46 PM   #1
Lexus Champion
Trader Score: (4)
t2d2's Avatar
Join Date: Apr 2014
Location: Oregon
Posts: 1,624
Default O2 sensor resistance (cold)

I replaced my main (upstream) O2 sensors today. I know they were replaced back around 50k miles, but I have no record of whether they were done over the past 140k, so I figured as long as I'm going to the trouble to pull them, I might as well have new ones on hand ready to install. I didn't have any CELs for them, but then again, it is OBDI.

Getting them out was tricky but not impossible. I used one of the offset O2 sensor sockets from Harbor Freight. That worked great on the driver's side, but required a wobble attachment on the passenger side to get securely on the sensor's base.

The hardest part was probably disconnecting (and reconnecting, on one side) the plugs. I was following the lexls DIY and the orientation seemed a bit different... I finally figured out the release tabs are on the top and you press down on the back portion to release the clip up front. I also had to straighten the pins to get one of the new ones to line up properly and clip back in.

Anyway, I measured the resistance of the old ones I took off, and they were 6.6 and 6.7 ohms at 74 degrees. The DIY and the service manual (specifically for the downstream sensors; didn't see anything about upstream) both say 5.1 to 6.3 ohms at 68 degrees, but no sliding scale with temperature changes like most sensors have. I would think the difference between 68 and 74 degrees is negligible as far as anything exhaust related is concerned, so is it safe to say my old sensors were out of range and a bit "lazy?"

I forgot to check the resistance of the new ones at the same temp's before plugging them in...

Interestingly, the old ones are labeled as Toyota 89465-24050 ND 065500-3491 4T and have a significantly shorter wire harness than the new Denso #234-4211 sensors. I'm guessing that means the old ones were factory replacements back in '98 at 50k. Shortly after that, the car disappears from dealer service records, making it unlikely a private mechanic replaced them in the interim.
This ad is not displayed to registered members.
Register your free account today and become a member on Club Lexus!
'94 SC400: Goodkat ... "It's not something people hear about. Falls on deaf ears mostly. This particular one has been over twenty years in the making."
t2d2 is offline   Reply With Quote
Old 07-26-14, 05:46 PM

Similar Threads
Thread Thread Starter Forum Replies Last Post
Diy - 01 Ls430 Code P0135 Oxygen Sensor Bank One Sensor 1 speedemon LS430 11 11-02-13 04:26 PM
P0420 CEL code for 98 ES300 need ohms. azcat90 ES300 and ES330 1 10-06-13 11:01 PM
Lower engine shield and o2 sensors nmikmik LS430 6 12-30-12 06:05 PM
Share my experience with Engine light/VSC/trac light wzwz8221 RX - Second Generation 2 12-16-12 06:10 PM
Oxygen Sensor ??? slmaol LS400 8 01-19-12 11:08 AM

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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

Forum Jump

All times are GMT -7. The time now is 06:04 AM.

Join ClubLexus

Copyright © 2000-2008 Internet Brands, Inc. All Rights Reserved
Privacy Policy | Disclaimer | Terms of Use | JOBS

Get all contact info