Switch Oled won't boots operates normally but won't charge while displaying charging icon

I have a brand new OLED switch here that won’t charge. It boots and operates as normal even displays a charging symbol when a charger is plugged in (15.2v drawing 0.2a, stops drawing when in standby) this current is just enough to maintain the battery whilst idle. The battery percentage does not increase.

I decided to mod it so I could have a look at the charging info in Hekate. Everything listed for the Max IC looks normal and capacity is correctly listed. The only red flag is that battery temp is always listed as cold which I’m thinking is what stops the charging. PD profiles are also recognised as normal.

I’ve tried another battery, checked the battery connector and USB C port (which were fine as expected on a new console). Checked for shorts around M92, Max, BQ and PI13 couldn’t find anything I also reflowed them. None of this remedied the problem.

I’m just wondering if anyone has seen this before with the battery temp being reported as cold causing no charging despite recognising the cable and indicating the console is charging.

What could be the culprit as Ive said no shorts, no physical damage to components or traces and on a brand new console. I’ve attached pics of the battery info from Hekate.

I’m fairly new to console repair and mostly mod consoles so my troubleshooting skills aren’t the greatest.

The bq will stop charging if the battery temp is to high.
That the temp is showing cold while not charging is like expected.

I would check that the 15 V are reaching the bq and if so, check that the VBat output at the bq has 4.2V while the charger is plugged.

Thankyou for the reply and picture to make it easy to check I’ll report back with my findings.

Just as an extra piece of information the battery temp shows as normal until the charger is plugged in and then changes to cold. Not sure if that is relevant.

So the vbus is getting 15v but the vbat is only getting 2.8v and 3.2v.

Does this suggest a problem with the bq chip?

If a charger is plugged in, vbat should show 4.2V (charging voltage → battery)
I guess your battery has 2.8V, if measured unplugged to the board.

I would check with a second battery, if the behavior is the same.

Same behaviour with a second battery unfortunately.

I have atm no oled board to make measuremts to compare the resistance of the temp pins at the bq. At an Erista board I have 5.5 kOhms at 20°C But my guess your value it is out of range.