80 series codes

[toyoteroMD]

Good day, I have a question about my cel. I have a 94 80 series, with my 02 sensor plugged in I get code 26(running rich) when i unplugged my 02 sensor i only get code 21(oxygen sensor) has anyone gone thru this. I have replaced IAC TPS INTAKE HOSE!!

 

[voodu3]

Here’s the areas to check from the fsm. It could be anything from a loose ground to a bad ecu.

 

[ppc]

One of the conditions for the diagnostic code 21 is either an "open" or "short circuit" in the O2 heater circuit. Disconnecting the sensor makes an "open" so the code 21 would be expected.

In the table above a code 26 can be caused by several items. One thing not listed and the most likely reason if failure of the O2 sensor. Over time the sensor can get "lazy" and not outputting a good strong in spec signal voltage. For that reason the sensor should be considered a wear item requiring periodic replacement.

 

[toyoteroMD]

thank you

Here’s the areas to check from the fsm. It could be anything from a loose ground to a bad ecu.

View attachment 2316790

thank you. I will look into it

 

[toyoteroMD]

One of the conditions for the diagnostic code 21 is either an "open" or "short circuit" in the O2 heater circuit. Disconnecting the sensor makes an "open" so the code 21 would be expected.

In the table above a code 26 can be caused by several items. One thing not listed and the most likely reason if failure of the O2 sensor. Over time the sensor can get "lazy" and not outputting a good strong in spec signal voltage. For that reason the sensor should be considered a wear item requiring periodic replacement.

Will be replacing them soon. Thank you for the add on

 

[retrofive]

Random, but when I fought a 26, I ended doing to some R&R on the EGR system.

 

[Rifleman]

Will be replacing them soon. Thank you for the add on

Just as an FYI O2 sensors are a maintenance item, and should be replaced accordingly. Depending on the type of O2 sensor, they may need to be change in as little as 60,000 miles of use, other types of O2 sensors can and do last longer then that, but they too will still need to be changed.