The vehicle in question is a 2004 Honda CRV w/ close to 190K. Original Alternator and Starter. I been chasing an engine Po134 for quite some time and finally got a scanner that allows me to see what the computer is doing at the point where it triggers it: The computer turns off the ground side control to the heater side.

I also bought one of those volt meters that you plug in cigarette lighter and found some interesting results.

Run 1
1. Clear engine code and start car,
2. RPM's are around 1100 when cold
3. Drive car normally
4. Has the car warms up around 3 miles, rpm's are dropping
5. The moment the check engine lights up, the voltage drops from 14.1 to 12.1
6. Is this a fluke or I got to 2 unrelated problems

Run 2
1. Clear engine code and start car,
2. RPM's are around 1100 when cold
3. Drive car hard, just like you stole it
4. I can maintain the light off for several miles as long as the rpm's are high
5. The moment the check engine lights up, the voltage drops from 14.1 to 12.1
6. Is this a fluke or I got to unrelated problems

 

Is it happening when the pcm attempts to enter closed loop?

 

No, the PCM goes to close loop very fast!

 

Does the scan tool show alternator duty or commanded charge duty?

If it is commanding a high charge duty and the voltage is dropping to battery voltage I would say the alternator is shot.

 

Not sure if my scanner can show the command charge level on my scanner

 

At what point is the heater sensor commanded off?

 

Pretty much at the same time the alternator volts drop to 12.1!

 

sorry I should have said is this normal
operarion for the circuit to be turned off ?

 

sorry I should have said is this normal
operation for the circuit to be turned off ?

I am not sure sure if this is normal or not.

The car still has the original alternator w/ 185k so it can also be the problem.

 

heater circuit can draw more power so makes sense that it would command high charging mode?! Someone knows...

 

Turn on the headlights and rear defroster and blower to high. That should be plenty to keep the system in high output mode.

 

OK,
I am going to try and turn on all accessories to see what the Voltage does, great idea!

 

Any luck?

 

It is funny that you ask for an update, I need to fix this leak first in order to continue more testing. I hope it is the smoking gun that I am looking!