2001 Ford Explorer Oxygen sensor

Most of the time the wires are routed near, or are clipped to the side of the tranny, If these guys either nicked a wire or got oil or grease on the sensor or connectors, this can happen!

Inbox :: Message
From: BillDollarLives
To: merlin2021
Posted: Mon Jan 28, 2008 8:38 am
Subject: Ford Explorer Oxygen Sensor
Dear merlin2021,
Thanks for taking the time to reply to my post regarding the bad Oxygen sensor. I suspected that this was the case based on the mechanic telling me over the phone that he was sure he had reattached the sensor correctly.
The check engine light was not lit when I picked up the truck. It happened after about 10 miles/15 minutes of driving. If the sensor was damaged during the installation of the transmission, why didn't the check engine light come on immediately? After I went back to the mechanic and he had reset the computer, the same thing happened, i.e., after about 10 miles/15 minutes, the check engine light came on again. Thanks for your time and I promise that this is the last question on this subject.
Andy...
Reply: Because the newer 4 wire sensors actually breathe thru the plastic insulation and connector...if it's oil contamination, and mind you I say IF...it can cause this problem! If it was a broken wire, it would have lit right away...If oil got on the base it would affect the heating element of the sensor...Again...when you start the car cold, the 02 sensors are not in the PCM loop! The PCM runs the engine rich until the 02 sensors heat up enough, then PCM enter closed loop and include 02 sensor info!