MN Murph

Would bringing the rpm's up or letting it run longer give a more accurate reading?

Lonwane

I believe it's called a LOAD TEST.

donbrew

My thinking is thus: if the ECM is broken and the ECM controls the alternator;
The computers are supposed to be able to operate on 10V, there are a lot of reasons that less than 10V gets to them even with a full battery.
The output of the alternator varies, it is not a constant 14.4V.
A slightly low battery usually manifests more as a failure of a sensor on the 5 V ref first, not the ECM.
QED : it is not the battery being slightly low but the ECM.

Yes, this is donbrew blaming the computer.

RJ_RS_SS_350

Thanks for the explanation, Don.

MN Murph

You guys thinks it's worth making a run to the salvage yard to grab a PCM out of a matching make/model/trim HHR?

Oldblue

Sure, why not! ? Maybe, try trickle charger on the battery and clean the posts!

donbrew

It will need to be programmed to your VIN. Are my posts showing up? I gave some links for programming way back in post #17.

MN Murph

This salvage yard has a parts store attached to it, stocked with salvaged parts. So I called them up cuz they got some for between 35 and 50 dollars online. The fella asked for the part number off mine. So I went to try to find it, and I don't know what I should and shouldn't touch or take out. How do you pull the PCM out and look at the number??

MN Murph

This is a picture of the receipt.
Not sure if this helps bring any closure to the battery question. But I wanted to rule that out as a possible issue.

Oldblue

Ok, thanks