trouble code 172

[98Rig]

so i had a code pop up when i was driving, happens only when i get to normal operating temperature. i have cleared the code and it pops back up when i get to normal operating temp. it says o2 sensor reads lean, is it bad or should i be looking somewhere else for the problem?

 

[MrShorty]

If this is on the '98 in your profile, you might want to post this in the 2nd gen forum, where people are more familiar with the EEC-V/OBD-2 set-up.

it says o2 sensor reads lean, is it bad or should i be looking somewhere else for the problem?

Yes, the O2 sensor might be bad, or you might need to look elsewhere for the problem. That's part of why lean O2 codes can be so hard to diagnose: there are so many things that can trigger them.

By the book, you usually start diagnosing O2 sensor codes by checking fuel pressure. Definitely check the wiring between the sensor and the PCM. Also check for vacuum leaks.

 

[BrooklynBay]

172
(R,M)
Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S - Fuel control.

This is an EEC-IV code. You have an OBD-II system in your 98.

 

[98Rig]

its a 92 explorer

 

[Tbars4]

...These threads might help...
http://www.explorerforum.com/forums/showthread.php?t=225221&highlight=172

http://www.explorerforum.com/forums/showthread.php?t=106175&highlight=172