2003 Isuzu Rodeo S
3.2L engine
automatic transmission

Was getting a code P0401 that I had insufficient
flow to my EGR valve, so I took it off and cleaned
the tube going down into the intake, and it cleared
it up, but I am getting two more codes, saying
both of my upstream O2 sensors have bad heaters.

Just put this engine in, no codes before.

What are the odds that my heaters went on both my O2
sensors, I don't see it likely.

Also, I have heard that these trucks will throw this code
for a leaking intake manifold gasket.
I had to remove it to install engine and thought maybe it
just might be.

Any help would be greatly appreciated, I have an emission
inspection to pass.

Thanks.

Will be around if you want more info, also, I know there is a fuse for
the O2 heaters, and it's good.

Also, when I checked the vacuum on the intake while truck
was running it was at exactly 20, dropped entirely when shut
off. Vacuum pressure remained in brake booster.

Also, if anyone does know how intake gaskets could affect this,
please enlighten me, because I want to know for next time
why both heaters won't work because of IMG leaks.

 

oh it'll throw all kinds of codes for all kinds of stuff, but this code usually means what it says. check voltages, wires & connections, ohms of the heater circuit (8-14) on the sensors if you don't want to replace the sensors blindly, replace one and see what happens....
- and remember, bank 1 is passenger side -

 

Pulled them both out. Ohmed them out, and nothing, out of limits, which tells me that they
are definitely no good, both are burnt out open loop POS's.

I also checked the voltage at the fuse and the O2 connections, and I had 12 volts for my source voltage.

I'm pointing fingers at o2 sensors, and will replace them and update...

 

Please correct me if I am wrong.

I am great with mechanical, but only about a year
in on electrical and having some issues grasping
it all...

 

you never really know what's right or wrong until you somehow fixed it!
I've heard it many times and experienced it myself: somehow things tend to burn up sometimes when the battery is dis- and reconnected. All of a sudden something is not working anymore to the point that the car won't start (while something completely different was fixed/worked on). Maybe weak ground points or such, I'll write a book as soon as I find out whats really going on :-)
But if you did the correct testing and get your out-of-limits results then you nailed it I would think. G'luck! (that's what a rodeo-mechanic needs :-)