1992 FJ80 Oxygen Sensor(s)? (1 Viewer)

[Hltoppr]

Ok,

1992 FJ80, 3FE with 197,000 miles.

Check Engine Light with code 21.....Oxygen Sensor malfunction.

Seems accurate, as my gas mileage has gone to hell....even for a 3FE.

Both oxygen sensors were replaced with OEM at 177,000 miles.

Any other reasons to get this code?

-H-

 

[cruiserdan]

If those are the original sensors you got your money's worth in spades. If those are the original sensors they are almost certainly shot and the source of the code 21

Oh crap, never mind.... I couldn't read the red font on the black background...

 

[cruiserdan]

Perhaps a broken wire? Do you have the FSM to follow the trouble logic tree?

It is also possible that you have a bad sensor, rare but I have seen it.

 

[Hltoppr]

Yeah, I've got the FSM.

IIRC the last time, when I replaced both, the diagnosis involved checking resistance in the wires leading up to the sensors. Both were out of spec. (presuming I did it correctly) so both were replaced.

When this started, the check engine light was intermittent, so I pulled the EFI fuse to reset it, and it came back on this morning.

-H-

 

[cruiserdan]

How old (time) are the sensors?

 

[Hltoppr]

Replaced in December 2003 IIRC.

-H-

About 20K miles.

 

[mpetersrx7]

You may want to read up of Fuel pressure regulator. This is a common code when the FPR goes bad. Check out the 3FE list on Yahoo or search the 60/62 board.

Hope this helps,
Mark

 

[Hltoppr]

Thanks Mark,

I'm pretty sure that the FPR and fuel pump are original, and I need to get around to replacing the fuel filter....

Dan, any info from Mr. T on the FPR/Code 21?

-H-

 

[cruiserdan]

I do not know of a tie-in between the two. That does not mean it is not possible, just that I'm stoopid about it.

 

[Hltoppr]

Ok, now the check engine light has turned off again....

I thought these things would stay on until you cleared them manually?

-H-

 

[fzj80kidpen]

Probably 2 trip logic.
Intermitten hell, it will come back.

 

[cruiserdan]

No two trip logic in the 92 that I am aware of. Much dumber than OBDII.

 

[Hltoppr]

Ok, is "two trip" like hippies at an extra set during a Phish show?

If it goes on and off, is that indicative that there may be a wiring issue or maybe the FPR?

-H-

 

[psfpilot]

two-trip

FYI, the 3FE, at least in my '92, has two-trip logic for codes 25, 26, 27; 71 according to the FSM.

 

[mytlc]

Is code 21 for 02 sensor HEATER failure? If so it would not require two trips to set, it would be instant trigger. It sounds like a possible wire/pin fit issue, would explain the light on/off. Either way the ECU is ignoring that sensor when that code is in memory, causing the poor fuel economy. Test wire/pin fit by wiggling the wire harness as you test with DVOM. Good luck

 

[80transit]

Where can I get an oxygen sensor the cheapest?

Ray
1993 FZJ80

 

[FrankTorres]

for the cheapest....
try NGK.com

 

[psfpilot]

Ok, is "two trip" like hippies at an extra set during a Phish show?

-H-

Two-trip logic means that the CEL stays dark after a single occurence of a deviation from the parameters that the OBD computer is monitoring. If the same deviation occurs on conscutive drives ("trips"), the waffle light comes on. For a little bedtime reading on this matter, follow along in your Manly Manual, page FI-23, and repeat after me...

 

[DawtSpot]

I'm getting codes 21 & 28 ... I just replaced the outermost downstream sensor & it didn't seem to solve the problem.

 

[jonheld]

I'm getting codes 21 & 28 ... I just replaced the outermost downstream sensor & it didn't seem to solve the problem.

O2 sensors should be replaced in pairs.
The Toyota FSM gives you the troubleshooting flowchart on page FI-44, assuming you have a 3FE.