O2 Sensors "Slow to Respond" ?? | Ford Explorer Forums - Serious Explorations

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O2 Sensors "Slow to Respond" ??

Tate Kyle

New Member
April 26, 2007
Reaction score
City, State
Snohomish, WA
Year, Model & Trim Level
'98 XLT
Hey everyone,

Let me preface this by saying although I am the son of a mechanic, I think I took him for granted when growing up and pretty much pretended to "pay attention" all those hours we spent in the garage together.
Well, my time has come and I am now paying the price.

Wifes '98 Explorer is throwing out these Fault Codes:
P0133: O2 Sensor Circuit Slow Response Bank 1 Sensor 1
P0153: O2 Sensor Circuit Slow Response Bank 2 Sensor 1

Now, does this simply mean that the circuit is bad? Or are there/could there be other underlying problems? Would you just replace these sensors and cross your fingers? What is happening here? This baby needs to pass emissions!

Thanks for your help and input.

How old are they???? It is possible that it is their "time". I do believe that a "normal" O2 sensor "oscillates" when it is functioning. "Slow to respond" likely means that the switching isn't happening at an acceptable rate. One reason may be that the heater is dead / dying. Another reason might be that the sensors are contaminated.

They are as old as the vehicle. 1998.