2023 PB - 'READY' indicator disappearing while driving

[FiveFourStillTickin]

Hi all, long time lurker. I've been soaking up the PB knowledge shared on this forum by Snakebitten, HammaMan, et al.

I've run into an odd one that I haven't been able to find any existing threads about. While the truck is in motion and transitions to electric power, the READY indicator in the instrument cluster disappears. No warnings, no loss of power steering/HVAC/infotainment, etc. Applying enough pedal to get the gas motor restarted and, voila, it's back.

I've had this happen 4-5 times over the last couple of weeks and some common themes I can think of:

• Truck remote started with key FOB, let it run ~10 minutes before getting in and pushing start button. READY pops up per usual on pushing START/STOP button and engine still running
• It's cold out - first couple of times I noticed it was in the 20s. Though this most recent occurrence it was almost 50. Happens both stationary in Park if engine is warm enough for HVAC demand and while driving
• Once I've been driving for 10-15 minutes or more, and engine comes up to full/near full temp, further transitions to electric only doesn't seem to trigger it. Parking for <30 minutes then driving again, hasn't happened

I've been through seemingly typical PB 12v SOC trials-and-tribulations (can elaborate if needed), and just recently replaced 2nd OEM under-hood battery with a NAPA and the under-seat aux with a new OEM (researching a better replacement, but had it on hand) and did a BMS reset. This was several weeks prior to the first time I've noticed READY's disappearing act. I did get a slew of OTAs after battery replacement/BMS reset, most recently the 10.1.0 update.

Logically, I'd fathom a guess it's related to a cold hybrid battery pack, but if that's the case I'd hope the engine wouldn't let the truck go into all electric mode until it's up to temp. Plus the electric motor IS still working while READY has disappeared, so maybe barking up the wrong tree there...

Given the manual's definition of the indicator, it's a bit unsettling that it turns off while the vehicle is in motion:

HYBRID ELECTRIC VEHICLE INFORMATION INDICATORS E293827 When you start your vehicle, a green READY indicator light appears in the instrument cluster letting you know that your vehicle is ready for driving. The engine may not start because your vehicle has a silent key start feature. This fuel saving feature allows your vehicle to be ready to drive without requiring the gas engine to be running. The indicator remains on when your vehicle is on, whether the engine is running or not, to indicate your vehicle is capable of movement using the electric motor, gas engine or both. Typically, the engine does not start unless the vehicle is cold, a climate control change is requested or you press the accelerator pedal.

Trying to figure out if any of y'all have ever experienced this and/or if this is a symptom of a bigger issue to come.

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[charlesdf22]

I’ve never seen this and I’m only a little further south of you with similar weather. Do your coolant levels look ok? I would check for codes and plan for a dealer trip.

 

[FiveFourStillTickin]

Thanks for the suggestion. I'll check coolant levels tomorrow and keep looking for DTCs.

Of course this morning - 29 degrees out, remote start, same in-town trip with some electric only driving - couldn't replicate. ?

 

[FiveFourStillTickin]

Got around to looking at coolant levels yesterday. I observed the larger expansion tank (high temp/engine as I understand) was sitting right at the MIN fill level, while the other (low temp/HV battery) was happily in the middle of fill range. This was with engine cold having sat all night. On a very slight incline, nose up, if that matters. Honestly never noted level when I took delivery, so maybe it came from the factory filled to MIN. Certainly something I'll keep an eye on.

I did notice a slight difference in perceived coolant color between tanks, with the smaller tank looking more bright neon green vs a duller yellow in the larger tank. AFAIK both loops take the same coolant. Maybe it's just the size and shape of the reservoirs and the light tricking my eyes. I did look around on the forum and what I'm seeing pretty much matches photos posted here by eharri3.

I did take a look at the exhaust heat exchanger after letting it warm up in the driveway. I'm aware there are various weep holes in the exhaust where you'd expect water to drip out when cold. But there was more or less a spray coming out of the heat exchanger. A closer look and it seems like this is also a weep hole, but the water spraying out seemed aggressive. Maybe that's just normal. I did a smell test on the puddle and luckily it does seem to just be water.

I do see the 24N04 CSP popping up in FordPass. Anyone have any luck getting dealers to take action on that yet? Conversation in this thread makes it sound like dealers aren't making appointments yet due to parts availability ?

 

[FiveFourStillTickin]

@kcarter good luck on the service appointment.

I'll attempt to replicate the key off/key on and PPoB issues you've observed and look for DTCs.

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