LBZ: DTC question

[bittles313]

Hello, truck in signature threw the #4 and #6 glow plug codes a couple of weeks back.Changed them, both codes went away.It got down to 15*F here the other night and when I started truck I got #6 code again and a P0128 code.My question is this, if grid heater isnt getting enough voltage will this cause or contribute to the P0128 I read that IAT is a factor in setting this code. I know it could also be stuck thermostat or bad ECT sensor. Reason for asking is that the original batteries are in truck from Oct 06.And am thinking that may be the place to start. Thanks in advance

 

[adeso]

how quickly does your temp rise?

 

[bittles313]

I only drove it a couple of blocks the other day to get my work truck. I will be taking it for a spin and checking things out in the morning.Truck only has 40,000 miles so it does sit alot which i'm sure doesn't help batteries either

 

[adeso]

Looks like that code goes with Tstats and ECT sending units. Not sure if other things can play into it

 

[bittles313]

Thanks,will be diving into figuring it out this morning...