So, this is the second time this has happened in the past few months. We were out of town for a couple of weeks in June and the 08 FEH wouldn't start afterward. I read all the posts I could find here, but I didn't do anything special to get it going again. IIRC, charged the 12V battery and pushed the jump start button for the HV battery (yes, you read that correctly, ours is an early 08 production that includes the jump start button). I don't remember if the jump button lit up or anything when pushed, but it eventually cranked.

Fast forward to now, and it's dead again. FYI, it has ~113k miles. It has sat for 10 days or so and no love with the starting. I'm realizing it's probably time to replace the 12V battery again (it's only on its second one). But for now my issue is how to get it going.

I've recharged the 12V battery (was reading 55% when I started charging). Everything in the cabin runs fine, but it won't crank and shows the wrench light (expected). I have OBD Fusion and that's showing 0% SOC and 282V on the HV battery.

I pushed the jump start button this morning, but it doesn't light up. Makes me wonder if it's vestigial in this in-between car. My one thought is to wait until the car has sat in the sun and warmed up to try again (so far have just fooled with it in the AM when it's in the 70s yesterday/today).

Open to suggestions as to what to do at this point. If I have to, I can build a HV charger from the old posts, but I'd rather not if there's another solution. Thanks!

 

Hopefully a more knowledgeable member will chime in but you may need to try the charger button several times. However, if your old low voltage is defective, I am not sure how much that will undermine the possibility of success. With a SOC of zero, that number also concerns me and casts a shadow over all your future efforts. It it were my vehicle and I wanted to try and save it, I would start with a new, 12V that meets Ford Spec. Getting one from the dealer is not such a bad idea. With the battery on an appropriate amperage charger ( I don't think I would use a low amp trickle charger in this situation) I would look at the archives here and try multiple button induced charges checking SOC after every attempt and go from there. Bear in mind you have a 13 year old battery which could be near end of life. Running the BCM and PCM module data streams and tests in FORSCAN can provide you with more information if your OBD Fusion only has simple features.

 

1. Disconnect the 12V for 5 minutes to wipe the codes.
2. Reconnect 12V.
3. Place 10A charger on 12V.
4. Press jump start.
5. wait 30 minutes.
6. Press jump start
7. wait 10 minutes
8. Attempt start.

 

Whew. OK. That did it. Thanks!

I had tried the jump start button the other day, but not with the specific 2x cycle/timing. It's weird b/c the light on the button doesn't light up, but today I noticed the voltage start dropping quickly after pushing it the 2nd time as I was switching my charger to 12A mode.

A couple minutes after cranking it, the SOC was reading 31% (after I went to grab wallet and wifi OBD dongle). I drove it about 7.5 miles on the highway and then another 10 on surface roads (4-lane with lights). It was in the ~44% range after the highway run, but it took maybe 3 more miles off the highway (with me speeding up and braking) to get into the low 50% range, topping out at 53% to 54%. All of this was with the ECON button off to try to push it to just charge the battery (that and it's in the 90s and I wanted the AC bad). This seems normal, though it seems like it takes a longer time recently to get to where it goes into EV mode.

I replaced the 12V battery, which probably was long overdue. I have noticed, similar to it taking longer to go EV, that the mileage has fallen off somewhat. For most of the time we've had it (we're the original owners), it got a steady 30 mpg. But that's dropped off to roughly 27 mpg over the past couple of years. It gets driven infrequently now and sometimes by my wife, who never really keyed in to the tricks to get the best performance. I'll be watching to see whether a new 12V battery helps with that.

Open to suggestions for things to look for that might also be affecting mileage. I have done plugs- forget when but my guess is 70k miles. I replace the air filters (battery, engine) about once a year. It's due for tires, but it has LRR Michelins that I keep at ~37 psig (I'm not a hypermiler, so no interest in going higher). I think we're not likely to keep it long term, but if there's anything inexpensive I can do to put it in better shape to sell before too long, I'd probably go ahead and do it.

 

If your HV battery is discharging below the start threshold in two weeks, it is severely deteriorated. I would expect it's the lion's share of your mpg loss as the car has to charge it more than normally.

 

Dumb question- IIRC, the HV will trickle to the 12V battery, right? If my 12V battery was toast, wouldn't that in itself tend to drain the HV battery more rapidly? I get that it's an old HV battery pack, but that seems like it might be a mitigating circumstance for assessing its condition based on recent events. FWIW, my guess without going to my file is that the 12V battery was put in around 2013 (or earlier); when I took it to Batteries Plus to get the new one, they said it tested at 1/2 its CCA rating.

Thanks for keeping the brain trust alive on the old FEHs.

 

The HV system provides 12V power and charges the 12V battery in operation. Sitting there in your driveway while off, it does nothing. Remember, the 12V battery does nothing but power the computers and accessories at startup. It never experiences a massive drain like a starter battery. It's common for these things to last a very long time.

If your 12V battery tests to 1/2 of its CCA, it's likely not a major factor in this situation.

 

Have been reading more and trying to be observant of what the car is doing when I drive it. Got a copy of Forscan Lite for my phone. It's good, but I like the dashboards I had set up in OBD Fusion b/c the displays are big enough I can read the numbers easily. I don't see how to access some of the tests (blend door, e.g.) that others have mentioned.

I was out of town, and my wife tried to hop in to take the dog to the vet. She told me she got a bunch of ABS warnings and that it felt very weird when she went to back out of the driveway. She pulled it right back in and used a different car. That was a Wed, and I drove it that weekend.

There weren't any warnings, but it is showing C1524-A0 and U2023-A0 in the ABS module. I've looked at the tone rings in the front, which seem fine as far as I can tell. My understanding is that the other thing to check, which I haven't, are the grounds.

Relevant to the previous discussion, I pulled up the SoC as soon as I could connect, and it was ~50% after sitting all week. I drove it for errands- probably 15 miles or so. Fast forward another week, and it was 18% after not being driven. And then 4-5 days more and it's still at 50%. So confused.

I also noticed driving it midday earlier this week (still in 90s at end of Sept) that the battery temperature got over 100F, and the engine did not shut off for the entire trip. During this time, the readout for the HV Evap Temp was 75F and the Cabin Evap Temp was 72F. Understand that it won't shut the ICE off when HV battery temp is too high.

Drove it this AM without issues and ICE did shut off (SoC 50% at start), but the highest battery temperature reading I saw was 86F (outdoor temp ~82F relatively early). When I stopped at my destination, I hopped out and checked in back. I'm due to replace the air filter, but I noticed no airflow across it. I don't totally get what to look for with the blend door (and I haven't gotten any warnings related to it). I pulled up the carpet and I could hear the cooling fan(s) running.

Open to more thoughts about what all I should be doing with this car. FYI, it did have the MECS pump replaced under warranty years ago.

On the earlier discussion, I did read an old GaryG thread where he thought that a bad 12V battery did affect mileage b/c the HV would just be dumping current into the 12V to recharge it for a long time after starting:

https://www.greenhybrid.com/forums/f...acement-15515/

 

Vampire drain on the 12V battery? This original owner has a trickle charger installed to minimize this issue on his 05 FEH. The aging HVB may also have an issue with an inability to hold its charge (SOC). Mine does and is going into the dealership in one day for a hybrid tech review.

 

Hi Gurus, I searched for my cranking issue in the forum, found a few posts, but didn't find anything that matched mine exactly. So I thought I would just post my question here. Related but not exact.

My 08 FEH also was parked for a couple of weeks and wouldn't crank when I tried to start. However, when I open the door and put the key in, all the lights light up, CD player works and everything. So I thought I must have some power left...battery is completely dead. I used my usual Li-Ion jumper battery to jump start it. That's worked before, but surprisingly, no crank this time. Now I'm stumped. Things I've tried:

1. I then charged my jumper battery to full overnight...still no crank.
2. Reconnected the leads multiple times to make sure I got good contact...no crank
3. Took the 12V battery out and brushed clean the terminals and clamps...no crank
4. The jump start button under the steering wheel has always been kind of inconsistent for me, so I've rarely touched it. The jumper battery I carry in the trunk has worked very easily several times. Anyway, I press the jump start button, but it just blinks and nothing cranks after waiting like 15 mins (according to the owners manual, blinking means low 12V battery).
5. I also took apart the ignition switch to see if the famously loose ignition switch is the problem, but it is not.
6. I checked some fuses in the fuse box under the hood but didn't see any obvious problems.
7. *Added After Posting* Sorry forgot to mention earlier. Plugged in an old school generic OBDII reader and got no codes. Tried several times, zero codes.

I did measured the 12V with a voltmeter and it was reading 9.7V. Now it's confirmed it's no good (maybe from me pressing the jump start button or maybe because it's old). But I don't know why it won't start even with the starter battery which has always worked before. I don't have the fancy scangauge readers you guys have, but I can see from the Ford display unit that the HV battery has little or no energy left, but that's not unexpected after parking for this long. In the past (before the pandemic), I drove the car once every 1-7 days and it's no problem at all. So that's my unscientific way of saying the HV battery should be "healthy enough" for an 08 FEH.

I don't have a trickle charger so I cannot get my 12V to get back to 12 volts. I could by one or buy a new battery, but I'm worried it could be a fuse or relay or some other component that's broken. Do you guys have any other ideas??? Much appreciate your help! Stay healthy, keep safe, and be well!

-mike