I am Throwing Code 21, 23, 41 on a JDM B16a 2ndgen. It is in a 94 Ex, using the Ex harness, and a P30 ECU.

I was only getting a code 1 at first w/ the O2 sensor that came w/ the swap. So I swapped the O2 sensor for the one that came out of my original engine. I no longer get a code 1. I get a code 21, 23, and 41.

Both O2 sensors looked the same and of the same condition; wires: 2black, a green and a white. The O2 sensor removed from my car was known to be good.

 

un plug the o2 and see if it throws same code!!! that should solve the problem

 

23 = knock sensor is it hooked up already??

21=VTEC Solenoid Valve defective circuit or unplugged / defective solenoid valve
* invalid code for non-VTEC engine
** invalid for V6 engine

41=Primary Oxygen Sensor - Heater circuit malfunction

 

the first two codes should be easy to get rid of. the code 41 though is a little tougher. that is for the heater element, which is always the two wires of the same color, in your case the two black wires. you need to find a ground and a 12v switched power source and you should be set.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JdmegFOUR &raquo;</TD></TR><TR><TD CLASS="quote"> un plug the o2 and see if it throws same code!!! that should solve the problem</TD></TR></TABLE>

I will try unplugging to see what happens.
yes, the knock sensor is already hooked up.

 

does vtec work when u drive it?

u forget to plug in the vtec plugs???

 

yes vtec does work and my a/f gauge is reading normally.
Before, when I was getting a code 1, my a/f was not reading at all.

 

I tried unplugging the O2 sensor and driving around a few miles. Check engine light came on and this time it throws code: 23 and 41.

When I plugged it back up it now, no longer throws code 21. It now throws code: 23, and 41.

 

maybe throw your old o2 back in..to see what happens...for that code 41...

also how did you hook up your knock sensor? the wire needs to be shielded and away from any heat and radio interference..its very very sensitive..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by white99gsr &raquo;</TD></TR><TR><TD CLASS="quote">the first two codes should be easy to get rid of. the code 41 though is a little tougher. that is for the heater element, which is always the two wires of the same color, in your case the two black wires. you need to find a ground and a 12v switched power source and you should be set. </TD></TR></TABLE>

could you elaborate more on this topic for code 41??

I'm having a similiar problem O2 Sensor

Don't mean to hijack your thread, but i need help.

 

Same here I got so fed up with the stupid code 41 I just converted to OBD1 but now I cant pass emissions

 

If I get a obd2-obd1 conversion harness, and a obd1 ecu will the codes go away?

I have a 99 ej6, stock d16y7, having major troubles with the wiring in my O2 sensors. Basically, one of the plug is having "heater wire" malfunctions that can be anywhere from the plug to the ecu. If I convert, will it solve, or at least make this problem go away??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by degooser &raquo;</TD></TR><TR><TD CLASS="quote">maybe throw your old o2 back in..to see what happens...for that code 41...

also how did you hook up your knock sensor? the wire needs to be shielded and away from any heat and radio interference..its very very sensitive..</TD></TR></TABLE>

I will try throwing the old O2 sensor back in and see what happens.
Now, re: The knock sensor, what should I use for shielding it against interference?

 

well i have no clue where get shielded wire, but i just took my jdm harness and took as much stock shielded wire that i can get...thats what i used....

 

How do you guys check coad and where? I got 2000 civic EX.