Think I need a new PEM Fan... Anything else to check?

gregd · Jun 22, 2020

Hi folks,

I just got the following alerts on my 2010 Roadster 2.0 (vin 5YJRE1A16A1000834). A bit under a year ago we were thinking the PEM fan needed replacement, but the evidence was inconclusive. The problem went away on its own so there was no way to verify a fix, and at $1,000, we decided to wait.

Today I got the following errors while the car was sitting in the garage, doing its daily top-off charge at 24 amps. PEM temp was 62C, so clearly it was not getting air. Ambient temperature was 24C.

06/22/2020 01:37:58 | 1592815078 | DAY | odo = 53936.3 range soc = 83%, brick ave 139.439Ah, brick min 136.588Ah, min Ah brick 14, CAC 136.88 Ah
06/22/2020 12:04:01 | 1592852641 | ERR | error code 1146 6 bytes
06/22/2020 12:04:01 | 1592852641 | ERR | error code 1144 6 bytes
06/22/2020 12:07:55 | 1592852875 | ERR | error code 1152 6 bytes
06/22/2020 12:07:59 | 1592852879 | ERR | error code 1074 6 bytes
06/22/2020 12:10:11 | 1592853011 | ERR | error code 1076 6 bytes
06/22/2020 12:11:59 | 1592853119 | ERR | error code 1078 6 bytes
06/22/2020 12:46:34 | 1592855194 | ERR | error code 1146 6 bytes
06/22/2020 12:46:34 | 1592855194 | ERR | error code 1144 6 bytes
06/22/2020 12:53:38 | 1592855618 | ERR | error code 1146 6 bytes
06/22/2020 12:53:38 | 1592855618 | ERR | error code 1144 6 bytes

Looking under the car, I see the PEM fan is not spinning. Using a stick, I could see that it could rotate (not jammed), though not super easily. I don't know what the proper spin resistance it should have, so that might be normal. Moving it did not start it spinning on its own, however, so thinking a bad spot on the brushes is not the cause. One time I noticed that it "twitched" ever so slightly when I woke the car up, after letting it go to sleep; it was followed immediately by an 1144 alert in the cabin.

Question: Are there any other things to check (e.g. fuses?) before considering a flatbed and Fan replacement? What other information do you need to determine the cause?

What do you guys think?

Thanks,

Greg

p.s. I also sent the above to [email protected]. We'll see if they respond.

ML Auto · Jun 22, 2020

The fan should spin very easily, if is binds at all it is bad. If it "twitched " a bit, it coould be a bad PEM connector. You would have to check for voltage at the fan (while plugged in) to determine the problem. Both the single and dual fan setups are Spal fan units and should be less than $200, so your $1000 quote is a joke. It is a simple job even if you have to lay on the ground to do it. A couple of hours tops.

gregd · Jun 22, 2020

The $1,000 (actually ($998 and change) was Tesla's quote for replacing the assembly last year, including their labor (which isn't cheap).

I tried repeating the "twitch" test, and it didn't move. The PEM had cooled a bunch by then, so perhaps it didn't need to run? Or, is it always running (even at a minimum rate), whenever the car is awake? I don't have a way to get under the car to do any voltage measuring, let alone trying to replace the unit.

The spin test was with a long stick, so it's hard to judge how easy it is to rotate. My main purpose was to see if it was simply a "flat spot" on the brushes, so moving it might get it going. No luck with that. But trying to "flick it" at a distance of about 3 feet with a stick did not send it spinning. Which way does it spin, anyway? CW or CCW when looking at it from the driver's side?

If it is the legendary connector on the bottom of the PEM, two things don't make sense. One, last September we went 9 rounds on this thing, and they poked and measured it, and proclaimed it was fine. So, it shouldn't be the problem, at least not so soon. Second, I would think the contacts would fail more slowly, i.e. I should have some 1144 errors errors in the logs for it from recent travel. I did have a bunch of 1115 and 1116 errors 2 weeks ago, but I believe they are related to the motor, and supposedly are diagnostic and likely erroneous. The last 1144 before today was last September, and the 1146's went away in early December (and I never did understand what the difference is, given that there is a single fan motor). So, my suspicion is that it is more likely a fuse, but I don't see one in the instrument panel set (passenger inside, by the door). Is there another place to look? Is it worth skinning my had to try to reach in and wiggle the connector under the PEM? It's almost impossible to get to.

Thinking ahead, a couple of related questions come to mind...

1. Without the fan, obviously, I can't drive the car any distance. I presume if I'm quick, I would hope that I could get it to the street for a flatbed pickup. It's short (50'?), but uphill. I was thinking that I might try blowing air into one of the side vents with a shop vac, to get some minimum airflow. Which side would I do that from? This is a 2.0; are they actually connected, or just cosmetic?

2. Without the fan, can the car charge from the 120v "granny" cord at, say, 8 amps, without overheating? Presuming this may take a while to resolve, I need to keep the battery up. Fortunately, it's at a full standard charge right now (160miles), so not a panic.

I really REALLY do not want to get the car down to Tesla on a flatbed and have it sit there waiting for one of their techs to get around to it. They put the cars outside, often in the sun. It's happened before, and in our 100+ degree summers, that could stress or damage the battery. Last time the ESS got to about 40C before I yelled at them enough times to get them to put the car inside. They really do not know how to treat these cars...

Thanks for your help!

jason.tv · Jun 22, 2020

what firmware do you have? I think you mentioned you have 4.6.0 or not the latest fw? Tesla can diagnose this for you and replace the motor fans; yes definitely get it flatbed to tesla and get a service appointment asap and make sure the service tech is able to do the car that day.

Maybe if need to charge dial down to 16amps once the pem is stable temp but that prob will have the same results.

gregd · Jun 22, 2020

jason.tv said:
what firmware do you have? I think you mentioned you have 4.6.0 or not the latest fw? Tesla can diagnose this for you and replace the motor fans; yes definitely get it flatbed to tesla and get a service appointment asap and make sure the service tech is able to do the car that day.

Maybe if need to charge dial down to 16amps once the pem is stable temp but that prob will have the same results.

Hi Jason,

Firmware is up to date, and has been for a while. No, this is a failure of something. Possibly the fan, possibly a fuse, possibly the infamous connector on the bottom of the PEM.

I have a LONG history with my Service Center, and up until a few years ago I would have no issue with giving them a call (where they'd answer the phone with "Hi Greg!") and arranging for the diagnosis and repair. Now, however, if I can even get them to answer the phone and get the car down there, it will (has in the past) sit there for days when they get overbooked. Your "appointment" is for the drop-off, NOT for having someone actually scheduled to work on the car. During that time, it's sitting outside under an open awning, shaded, perhaps, but otherwise sitting in a 100+ degree heat. For the past 3 annual service events, the car has been returned to me in worse shape than when it went in, once almost fatally (they didn't hook the fan housing to the underside of the PEM properly, and it overheated). I'm not driving much due to being retired and with the pandemic, so was planning to not go for the annual until next year, over fear and trepidation that they'd mess something else up again.

So the reason for the thread is to be sure that I haven't missed something more-or-less simple that I can take care of myself. My service experience has been that bad.

hcsharp · Jun 22, 2020

There are 2 fuses for the PEM fans under the small access panel on the right side top of the PEM. I think they're 25A? Not sure but they're easy to get to.

You won't have any trouble driving the car a couple hundred feet with no fans. But don't take it to Tesla if it's just going to sit outside. You could replace the fan yourself in the time it takes to transport the car there and back.

gregd · Jun 22, 2020

hcsharp said:
There are 2 fuses for the PEM fans under the small access panel on the right side top of the PEM. I think they're 25A? Not sure but they're easy to get to.

You won't have any trouble driving the car a couple hundred feet with no fans. But don't take it to Tesla if it's just going to sit outside. You could replace the fan yourself in the time it takes to transport the car there and back.

Ok, good to know. I'm upset enough with their service that I may just do that.

The fuses... I presume I need to disable APS before opening the cover, right?

gregd · Jun 23, 2020

So it appears that I can charge the car for a few minutes on 120v, but then the PEM starts heating up. Haven't tried using the shop vac to pump air in... Which side is the PEM intake on? (This is just so I can buy time for the real solution...)

Trying again with the stick, the fan doesn't seem to be hard to turn, so I don't think it's a bad bearing (or at least, not a seized one). It still fails to twitch when the car wakes up. When does the fan turn on? Temp-only, or all the time?

Regarding the PEM fuses, I'm looking at some of the pictures of the area under the cover. Before I open things up, which are the fuses (on the side?), and what type (so I can get a set before hand)?

X.l.r.8 · Jun 23, 2020

If you have single fans, pretty sure you have the single motor setup but unsure. Gruber has the single motor set up for a great price, I can recommend T7Design for the dual motor (separate units)

That was for 2 fans, I wanted spare units.

gregd · Jun 23, 2020

Thanks for the pointer. The car does have the single motor / dual blower fan, and it is my understanding that it provides more airflow than the pair of separate units. Ambients here can top 100F / 37C, so more air is a good thing to have. Looks like Gruber has one for $187.

I got a reply from RoadsterServiceNA (Matthew), with not much help ("take the car to the SC for diagnosis"). He did give a pointer to a Tesla site for uploading the logs for further analysis (apparently they won't accept them via email), but the upload fails. {sigh} Why am I not surprised. I've asked for help on the upload by return email.

I tried aiming a shop vac hose (on "blow") at the driver's side fan opening, hoping I can force enough air to keep the PEM cool enough for a top-up charge. It helps, but temps still climb above 50C in a few minutes, on either 120v or 240v charging. Might try to block off the opening a bit, and see if that helps. The PEM's blower is the one on the driver's side, right? Seems the ducting goes that way, but I cannot find a picture with labels.

hcsharp · Jun 23, 2020

gregd said:
The fuses... I presume I need to disable APS before opening the cover, right?

It will disable automatically when you open the cover but I recommend disabling it beforehand. The fuses are on the side. Standard automotive small blade fuses.

hanknum · Jun 23, 2020

Sorry to hear Greg... I hope you get it sorted out. I will be watching and learning though.

Henry

Bunnak · Jun 23, 2020

gregd said:
Hi folks,

I just got the following alerts on my 2010 Roadster 2.0 (vin 5YJRE1A16A1000834). A bit under a year ago we were thinking the PEM fan needed replacement, but the evidence was inconclusive. The problem went away on its own so there was no way to verify a fix, and at $1,000, we decided to wait.

Today I got the following errors while the car was sitting in the garage, doing its daily top-off charge at 24 amps. PEM temp was 62C, so clearly it was not getting air. Ambient temperature was 24C.

06/22/2020 01:37:58 | 1592815078 | DAY | odo = 53936.3 range soc = 83%, brick ave 139.439Ah, brick min 136.588Ah, min Ah brick 14, CAC 136.88 Ah
06/22/2020 12:04:01 | 1592852641 | ERR | error code 1146 6 bytes
06/22/2020 12:04:01 | 1592852641 | ERR | error code 1144 6 bytes
06/22/2020 12:07:55 | 1592852875 | ERR | error code 1152 6 bytes
06/22/2020 12:07:59 | 1592852879 | ERR | error code 1074 6 bytes
06/22/2020 12:10:11 | 1592853011 | ERR | error code 1076 6 bytes
06/22/2020 12:11:59 | 1592853119 | ERR | error code 1078 6 bytes
06/22/2020 12:46:34 | 1592855194 | ERR | error code 1146 6 bytes
06/22/2020 12:46:34 | 1592855194 | ERR | error code 1144 6 bytes
06/22/2020 12:53:38 | 1592855618 | ERR | error code 1146 6 bytes
06/22/2020 12:53:38 | 1592855618 | ERR | error code 1144 6 bytes

Looking under the car, I see the PEM fan is not spinning. Using a stick, I could see that it could rotate (not jammed), though not super easily. I don't know what the proper spin resistance it should have, so that might be normal. Moving it did not start it spinning on its own, however, so thinking a bad spot on the brushes is not the cause. One time I noticed that it "twitched" ever so slightly when I woke the car up, after letting it go to sleep; it was followed immediately by an 1144 alert in the cabin.

Question: Are there any other things to check (e.g. fuses?) before considering a flatbed and Fan replacement? What other information do you need to determine the cause?

What do you guys think?

Thanks,

Greg

p.s. I also sent the above to [email protected]. We'll see if they respond.

I also had alert 1146...kept driving for couple weeks and ignored it then eventually got an alert 947 (System Too Hot Vehicle Shutting Down). I needed a new fan.

Bunnak · Jun 23, 2020

gregd · Jun 24, 2020

@Bunnak yes, it certainly looks that way. I'm going to attempt the fuse thing first (under the cover), hoping that a history of trying to push the fan hard caused one of them (the PEM side) to fail, and that replacing it will let the motor run long enough to get it into a service situation. I haven't decided whether that will be at the Tesla SC or my own garage. Cost tells me to do it here, the hassle factor is undecided, unfortunately. A major hassle either way. I'm tempted to do it here, just because the past 3 years Annual Maintenance have resulted in a car that was less reliable than when it went in, so I fear I will need to be able to work on this myself sooner rather than later.

Question to anyone who has replaced the fan assembly: Is it just common screw driver + wrench sorts of bolts, or does one need to remove any of the suspension parts? I draw the line at the suspension, and that bar that goes across the unit looks scary. I also have no idea how I am going to raise the car up enough to get under it.

EDIT: Oh, and a PSA to anyone who is depending on OVMS to alert them to the dreaded 1144 / 1146 messages. At least on my Android version, they are suppressed because they are considered "diagnostic" messages. However valuable, especially to warn you before the car actually shuts down on the freeway, they're no longer presented in real time. You have to grab the logs and look manually.

drewski · Jun 24, 2020

gregd said:
@Bunnak yes, it certainly looks that way. I'm going to attempt the fuse thing first (under the cover), hoping that a history of trying to push the fan hard caused one of them (the PEM side) to fail, and that replacing it will let the motor run long enough to get it into a service situation. I haven't decided whether that will be at the Tesla SC or my own garage. Cost tells me to do it here, the hassle factor is undecided, unfortunately. A major hassle either way. I'm tempted to do it here, just because the past 3 years Annual Maintenance have resulted in a car that was less reliable than when it went in, so I fear I will need to be able to work on this myself sooner rather than later.

Question to anyone who has replaced the fan assembly: Is it just common screw driver + wrench sorts of bolts, or does one need to remove any of the suspension parts? I draw the line at the suspension, and that bar that goes across the unit looks scary. I also have no idea how I am going to raise the car up enough to get under it.

EDIT: Oh, and a PSA to anyone who is depending on OVMS to alert them to the dreaded 1144 / 1146 messages. At least on my Android version, they are suppressed because they are considered "diagnostic" messages. However valuable, especially to warn you before the car actually shuts down on the freeway, they're no longer presented in real time. You have to grab the logs and look manually.

you can back onto ramps (i have Rhino ramps) to get to the fan.

you will have to loosen the sway bar (the scary bar) to easily get at at least one of the lower fan mounting bolts. you don't have to remove the bar entirely -- just the 4 bolts holding the sway bar bushings to the bulkhead.

it's not scary.

Roadster · Jun 24, 2020

Relatively straight fwd job with basic tools @gregd. Detailed instructions with photos and video here.

gregd · Jun 24, 2020

drewski said:
you can back onto ramps (i have Rhino ramps) to get to the fan.

you will have to loosen the sway bar (the scary bar) to easily get at at least one of the lower fan mounting bolts. you don't have to remove the bar entirely -- just the 4 bolts holding the sway bar bushings to the bulkhead.

it's not scary.

No adjustment / alignment of the bar after reassembly? Just bolt it in place and it's good?

Which model Rhino ramps (or dimensions)? I see one on-line that say they're designed for low-clearance vehicles. 8 1/2" tall. Is that enough to get under the car to work on it? I'm not a big person, but this doesn't sound like fun...

drewski · Jun 24, 2020

gregd said:
No adjustment / alignment of the bar after reassembly? Just bolt it in place and it's good?

Which model Rhino ramps (or dimensions)? I see one on-line that say they're designed for low-clearance vehicles. 8 1/2" tall. Is that enough to get under the car to work on it? I'm not a big person, but this doesn't sound like fun...

i have the low clearance ones and this won't impact the alignment.

I'm somewhat close to you (I think - Oakland) so depending on when you're thinking of doing the swap, i may be able to help.

gregd · Jun 25, 2020

drewski said:
i have the low clearance ones and this won't impact the alignment.

I'm somewhat close to you (I think - Oakland) so depending on when you're thinking of doing the swap, i may be able to help.

Thanks. I'm in the Foothills, about 30 mi NE of Sacramento. It'd be a long drive for you, but perhaps some live phone advice might be a starting place. Not there yet...

An update. I inhibited the APS, and opened The Cover to look at the fuses. They're 20 amp models on my car, and both check out good. So, that's not it.

I may try to stick my hand through the port hole in the trunk to see if I can wiggle the fan connector a bit. Not as a fix, but rather to see if rubbing off a little corrosion might be enough to prove where the fault lays. As I recall, however, the connector is pretty tightly anchored, so I doubt that I can get enough force on it to do anything.

Any other ideas?

Think I need a new PEM Fan... Anything else to check?

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