CEL Codes 25 & 26 on 93 FZJ80??

EricG · 04-17-09, 09:11 PM

Hey Guys,
CEL came on on the way home tonight. Shorted E1 & TE1 and got codes 25 and 26. Which seems kind of weird as 25 indicates a lean condition and 26 indicates a rich condition?!?

The truck runs fine - no noticeable difference. No recent maintenance. Had it out today to play in the snow a bit - lots of wet slushy stuff, and lugging and/or revving the engine a bit more then normal street driving. But nothing extreme at all.

Truck has about 175K on it. Could this be an O2 sensor issue, particularly if they got splashed by the crud. I got the truck at 104K and haven't touched them.

Any suggestions appreciated!

supercarrera · 04-17-09, 10:12 PM

Any signs of the truck running badly like a missfire? When mine was throwing 25 and 26 simultaneously, it turned out to be a bad fuel injector. It was having a noticeable missfire and running rough.

MARLIN375 · 04-17-09, 10:22 PM

My Son stuffed the truck into a snow pile afront the house while it was still warming up and I believe it fried my sensor pre-heater circuit. I could not clear the CEL by pulling the EFI fuse and was throwing the dredded 81,82,83 or the like along with the 21 ...meaning my ECU was hooped and the sensor was bad. I replaced the ECU with the newer one 89661-60221 and still have the CEL with 2 new sensors on the way.

It is not the same situation as yours but I saw "snow" and "sensors" on a 93 and thought I would share.

EricG · 04-17-09, 10:46 PM

Quote:

Originally Posted by supercarrera

Any signs of the truck running badly like a missfire? When mine was throwing 25 and 26 simultaneously, it turned out to be a bad fuel injector. It was having a noticeable missfire and running rough.

Not at all. It feels/sounds fine.
I'm going to pull the EFI fuse tomorrow to clear the codes and see what comes back.

EricG · 04-17-09, 10:49 PM

Quote:

Originally Posted by MARLIN375

My Son stuffed the truck into a snow pile afront the house while it was still warming up and I believe it fried my sensor pre-heater circuit. I could not clear the CEL by pulling the EFI fuse and was throwing the dredded 81,82,83 or the like along with the 21 ...meaning my ECU was hooped and the sensor was bad. I replaced the ECU with the newer one 89661-60221 and still have the CEL with 2 new sensors on the way.

It is not the same situation as yours but I saw "snow" and "sensors" on a 93 and thought I would share.

What's a "sensor pre-heater circuit"? Is that with the O2 sensors?

Anyway, I didn't plow into anything deep or hard. Maybe 8" tops. But very slushy some places - I'm wondering if something got wet from the spray that shouldn't have.

MARLIN375 · 04-18-09, 09:21 AM

As I understand it the sensor has a heating circuit (two of the four wires) that operates at startup to decrease the time it takes your truck to get to a closed loop condition. It runs in an open loop until your sensors gets to operating temp (something like 400 degrees IIR).

EricG · 04-18-09, 12:25 PM

Cleared the codes this morning, then drove into town. Made a few quick stops, came home. Probably 30 miles total. Light didn't come back on. So I guess I'm in wait-and-see mode now.

jlbuk · 04-18-09, 04:07 PM

My '93 did the same (25 & 26) when I floored it a while back (3k revs). CEL cleared itself after maybe 10 mins driving. It did it ths same again a couple of weeks later. Not done it since (a month or so), so I'm ignoring it for the moment...

History: car one new O2 sensor (walker), rest stock/old

Not sure if this helps ! JB

Schnieb · 04-18-09, 09:54 PM

I had the same code on my 92 last week and replaced both o2 sensors, code hasn't come back yet and runs much better.

EricG · 06-08-09, 10:00 PM

I took this into the dealer today to get their opinion. They pulled codes 24 (Intake air temp. signal) and 25 (air fuel ratio lean) and said both the O2 sensors were reading bad.

So will likely be replacing those. I've also got an exhaust leak somewhere, rear strap on the muffler is broken, and the muffler is splitting a seam - so I may do the whole exhaust from the downpipes back. Time for some more mud-search.

EricG · 07-27-09, 06:21 PM

Just got it back from the shop - new O2 sensors and new 2.5" exhaust system from the downpipes back. Dual inlet cat and a "two pass truck muffler" according to the guy at the shop. Runs like new! Maybe just placebo effect, but it really feels more responsive/better pick-up.

Just very slightly louder then stock I think - though it's been awhile since I heard it stock given the number of leaks I had around the O2 sensors & cats.

Oh yea ... and no more CEL

Though that was somewhat intermittant and I've only driven it a few miles at this point.