'94 FZJ80 CEL goes ON only for a few minutes when cold, DTC #25 or #26 in memory (1 Viewer)

[A2ShedsJackson]

When I have had codes in the past they would stay ON until the problem was repaired. Recently when the engine is cold and I drive for a mile or few the CEL comes ON and then turns off after a couple minutes. The CEL does not return until after the engine is off and returns to a cold temp after many hours/overnight. The codes that are stored are #25 or #26 or both. Maybe it's time to replace the original O2 sensors with 350K miles. What have you noticed with this issue?

 

[ZackR]

Original 02 sensors with 350K miles are definitely due for replacement. I just installed new ones in mine yesterday after removing the PAIR system. Although I wasn't getting a CEL mine ran like crap when cold and at low RPM with the old sensors. It ran much better with them unplugged (CEL on), and should do even better with the new ones.

The NTK 24080 units are made in Japan and the wiring harness will reach both of them in the PAIR location.