P1448 Bad IPU IMA Hybrid Cooling Fan Motor ... Can it be fixed?
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So I replaced the ima fan with an aftermarket from rockauto and that fix the problem temporary, I didn't work at the beginning but after driving for like 10 min start at full blast it did work like that for like 40 min and then start to slowing down and stop working , again code p1448 showing together with P0A7F
Should I get the OEM fan or it might be the battery going out ?
Also when code p1448 is present and the Temperature outside is +90 degrees Fahrenheit the 12v battery stop being charge and the red battery light lit after driving like that the car start loosing A/C , steering, etc and then stall
Please help
2005 Honda Accord hybrid
Should I get the OEM fan or it might be the battery going out ?
Also when code p1448 is present and the Temperature outside is +90 degrees Fahrenheit the 12v battery stop being charge and the red battery light lit after driving like that the car start loosing A/C , steering, etc and then stall
Please help
2005 Honda Accord hybrid
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This is the wrong forum for the 2005 Accord hybrid.. However...
Did you clear your old IMA fan code properly after installing the new fan?
If not it might still be there waiting to be read.
P0A7F is IMA battery deterioration IIRC so you have more than just a possible fan problem.
As your IMA battery is bad, it is shutting down the DC-DC so the 12v battery is not being charged, hence losing AC, steering and car stalling etc.
You need to fix the IMA battery, speak to Bumblebee batteries in the US.
Have you checked for things like blocked IMA inlet and outlet vents.
Mice make nests in weird places. If the code really has come back try and get a proper fan from a breakers yard.
Did you clear your old IMA fan code properly after installing the new fan?
If not it might still be there waiting to be read.
P0A7F is IMA battery deterioration IIRC so you have more than just a possible fan problem.
As your IMA battery is bad, it is shutting down the DC-DC so the 12v battery is not being charged, hence losing AC, steering and car stalling etc.
You need to fix the IMA battery, speak to Bumblebee batteries in the US.
Have you checked for things like blocked IMA inlet and outlet vents.
Mice make nests in weird places. If the code really has come back try and get a proper fan from a breakers yard.
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I recently got a bad fan back from a UK CR-Z owner who had the P1448 fault.
This video shows good V bad fan bench test using a 12V current limited power supply.
Note the bad fan may not move at all in this test, and visual inspection might reveal clearly blown mosfets. (This fan did not have obvious visual mosfet damage)
Anyway after removing the pcb from the motor and testing the bad fan 6 x mosfets with a multimeter on basic continuity, it shows a blown (short circuit) mosfet that I have now removed.
You can buy them on e-bay for $5 for ten so it should be a case of simply soldering in a new one and off we go.
Note the solder on the PCB is high melting point. I had to turn my soldering iron upto 480C before it would melt properly.
Careful you don't mangle the pcb traces.
The NEC K3755/2SK3755 mosfet is a slightly narrow TO-220 insulated body type and I don't have any suitable in stock, so will order some and report back when fitted.
Might be a while on the slow boat from the far east. Note you could use any compatible pinout similar spec N Channel part.
Data sheet attached.
This video shows good V bad fan bench test using a 12V current limited power supply.
Note the bad fan may not move at all in this test, and visual inspection might reveal clearly blown mosfets. (This fan did not have obvious visual mosfet damage)
Anyway after removing the pcb from the motor and testing the bad fan 6 x mosfets with a multimeter on basic continuity, it shows a blown (short circuit) mosfet that I have now removed.
You can buy them on e-bay for $5 for ten so it should be a case of simply soldering in a new one and off we go.
Note the solder on the PCB is high melting point. I had to turn my soldering iron upto 480C before it would melt properly.
Careful you don't mangle the pcb traces.
The NEC K3755/2SK3755 mosfet is a slightly narrow TO-220 insulated body type and I don't have any suitable in stock, so will order some and report back when fitted.
Might be a while on the slow boat from the far east. Note you could use any compatible pinout similar spec N Channel part.
Data sheet attached.
Yes , I did clear the codes with the scanner, disconnecting the 12v battery for a few min. And then run the scanner again, there wasn't any code on the computer so I went for a test and after 10 min. Of driving the fan kick in at full blast like crazy loud 📢 after of driving for 45 min. The fan start slowing dying, stop and turn on again , hook the scanner and saw that the 12v wasn't being charge and the 2 codes come back.
I want to mention that I got a grid charger hook and went I use it the fan works at high speed.
I did check the grid connection to make sure everything is good .
Also I haven't check the entire duct from the battery to the fan but I did take off the fan and the 2 pieces on both sides inside the trunk there is not blockage because I can feel the air when the fan was working at full blast
Thank you for your reply
Really good info, I would like to know which MOSFET are you referring too and if you test the continuity with the MOSFET still soldered to the board?I recently got a bad fan back from a UK CR-Z owner who had the P1448 fault.
This video shows good V bad fan bench test using a 12V current limited power supply.
Note the bad fan may not move at all in this test, and visual inspection might reveal clearly blown mosfets. (This fan did not have obvious visual mosfet damage)
Anyway after removing the pcb from the motor and testing the bad fan 6 x mosfets with a multimeter on basic continuity, it shows a blown (short circuit) mosfet that I have now removed.
You can buy them on e-bay for $5 for ten so it should be a case of simply soldering in a new one and off we go.
Note the solder on the PCB is high melting point. I had to turn my soldering iron upto 480C before it would melt properly.
Careful you don't mangle the pcb traces.
The NEC K3755/2SK3755 mosfet is a slightly narrow TO-220 insulated body type and I don't have any suitable in stock, so will order some and report back when fitted.
Might be a while on the slow boat from the far east. Note you could use any compatible pinout similar spec N Channel part.
Data sheet attached.
Also is there any chance to have the fan jumped from the pins that you try permanently so the fan sis always running ?
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My far eastern cheap mosfets arrived and I replaced the duff item and the fan now appears to work on the bench.
I might swap it into my test car to see if it faults when under car control.
It's a two minute job to swap it out with all the interior removed.
I can carry the known good one with me and swap it at the roadside if need be.
I might swap it into my test car to see if it faults when under car control.
It's a two minute job to swap it out with all the interior removed.
I can carry the known good one with me and swap it at the roadside if need be.
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My IPU fan failed about a month ago. The IMA2 fuse was blown, the entire electric motor system shut itself down, and it started throwing the P1148 code. After reading the posts and watching the videos here, it gave me the idea to check the MOSFETs and test the fan on a bench power supply. One of the MOSFETs (the one behind the big inductor in my case) was reading a dead short across all three of its pins. It didn't have any cosmetic flaws or burn marks, but I assumed that it was the root of my problem. Getting the circuit board separated from the fan motor required drilling some 2.5mm (~3/32-7/64in) holes in the spot welded pins and prying them apart with a small screw driver. I removed the bad MOSFET (with some difficulty, due to silver solder on the same pad as a giant heat sink) and replaced it with one of these that I found on Mouser. The fan spun up just fine and hit quite an incredible speed compared to the bumpy, anemic performance it had with the bad MOSFET. After plugging the fan back into my CR-Z, the IMA2 fuse no longer blows immediately and the fan seems to be running just fine. I'm definitely making sure I have an up to date fire extinguisher with me while I drive just in case, but so far it seems to be working out great! I'll try to post back with an update to let everyone know how things are going in a month or two to see if my repair has any longevity. All in all it looks like I just spent about 2$ and roughly 6 hours of my time to fix a problem that the dealer quoted me at ~$850 or ~$150-200 if I were to purchase the replacement fan myself. Thanks a ton for leading me in the right direction!
In case anyone is curious, I believe that this is the original MOSFET used on the board, but they are no longer being produced and are only available in quantity to existing customers. The replacement MOSFET I selected was simply the closest in spec (rated higher than the existing one) that I could find in stock on a major electronics distributor's site.
In case anyone is curious, I believe that this is the original MOSFET used on the board, but they are no longer being produced and are only available in quantity to existing customers. The replacement MOSFET I selected was simply the closest in spec (rated higher than the existing one) that I could find in stock on a major electronics distributor's site.
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Well, that didn't last long... Took it out on a second drive, heard a quiet pop while stopped at a light, and the car died. Blown IMA2 fuse and P1148 all over again. Took it back apart and the replacement MOSFET had also blown. My best guess at this point is that something else is broken on the fan board that is causing the MOSFET to fail as the one I used as a replacement was higher rated in almost every way compared to the original. I went ahead and ordered a replacement OEM fan which should be here next week, so hopefully that finally kills this issue for good. At least I had a lot of fun and learned a lot along the way on this repair, as frustrating as it was to have it not work out in the end.
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Maybe something else on the board failed or perhaps more than one mosfet but in a more subtle way or the motor windings were bad.
Unfortunately it's a common problem and they are clearly not a great design.
Unfortunately it's a common problem and they are clearly not a great design.
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Just wanted to follow up on my fix. After installing a replacement OEM fan, the car has run fine ever since. It has now been about 5 months and I've driven over 10,000 kilometers without any additional issues.
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I have just been fixing another failed IMA fan today from a UK owner.
This one had two mosfets that had failed short circuit on one of the phases of the bridge allowing a direct short between 12V and GND.
This causes fuse 53 to blow immediately disabling the IMA system and not giving the normal P1448 fan code because the IMA 12V side has no power.
I have replaced the two blown mosfets and it now seems to be working fine on the bench.
So if your fuse 53 blows immediately it is replaced, unplug the IMA fan.
If it no longer blows the fuse with the fan unplugged then you have located the fault.
I think I will offer an exchange repair service on the these fans in the UK for £110.
If your fan dies you contact me I send you one the next day.
You post your dead one back to me when it has been swapped out.
This one had two mosfets that had failed short circuit on one of the phases of the bridge allowing a direct short between 12V and GND.
This causes fuse 53 to blow immediately disabling the IMA system and not giving the normal P1448 fan code because the IMA 12V side has no power.
I have replaced the two blown mosfets and it now seems to be working fine on the bench.
So if your fuse 53 blows immediately it is replaced, unplug the IMA fan.
If it no longer blows the fuse with the fan unplugged then you have located the fault.
I think I will offer an exchange repair service on the these fans in the UK for £110.
If your fan dies you contact me I send you one the next day.
You post your dead one back to me when it has been swapped out.
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I now have three fixed IMA fans in stock for UK/EU owners if needed.
I managed to repair the latest one just now by replacing two mosfets.
These had not completely failed but were bad enough that the fan would not start occasionally depending on where it stopped.
The fan driver times out after a few seconds if the fan does not start rotating, probably to prevent damage to the drivers if the impeller is locked.
So this could/would cause an annoying intermittent P1448 as sometimes it would start and other times it might not.
If anyone in the UK has a dead IMA fan sitting around please send it to me. Thanks...
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Same part for a USDM car?
View attachment 69343
I now have three fixed IMA fans in stock for UK/EU owners if needed.![👍]()
I managed to repair the latest one just now by replacing two mosfets.
These had not completely failed but were bad enough that the fan would not start occasionally depending on where it stopped.
The fan driver times out after a few seconds if the fan does not start rotating, probably to prevent damage to the drivers if the impeller is locked.
So this could/would cause an annoying intermittent P1448 as sometimes it would start and other times it might not.
If anyone in the UK has a dead IMA fan sitting around please send it to me. Thanks...
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Yes...
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So what are the common failure modes for the 3 phase BLDC (Brushless DC) IMA fan?
![Product Font Rectangle Parallel Pattern]()
My examination so far of a few dead fans shows the failure is always in one or more of the 6 Mosfet Transistors on the metal heatsink.
These are labelled SW1-6 in the generic image above.
We currently have two distinct failure modes...
1) If just one of the six power Mosfets fails then the motor may still work to a degree but.....
a) It may not be able to start depending on where the impeller stops. (The fan driver times out after a few seconds if it does not start rotating)
b) It may not reach the correct speed (rpm) due to lack of power from the blown Mosfet section.
(This is why some owners report they can hear it working but still have a fan error code P1448 and no IMA function)
The fan has a speed sensor feedback circuit, and with a certain drive power the MCM expects it to reach certain set speeds (rpm)...
2) If two Mosfets have failed short circuit (allowing current to flow when not commanded)
then this can set up a direct short circuit between the + and - power feeds which immediately blows the under dash fuse 53.
The system is unable to detect this as a fan fault and set code P1448 as the power to the MCM/BCM is lost when the fuse blows.
Conclusions.
If the fuse is immediately blowing and you have no fan related code then it's likely two or more fan Mosfets have failed.
Simply unplug the fan and then replace the fuse to confirm if it is responsible.
If it doesn't blow with the fan unplugged you have the answer.
If you just get P1448, sometimes intermittently and the fuse does not blow, then it's likely one Mosfet has failed or is failing.
Visual detection of which one/s has/have failed is sometimes possible if the Mosfet package has been damaged. (Blown/burnt)
Of course there may be other rare failure modes we haven't encountered yet, but I suspect the above covers 99% of them.
My examination so far of a few dead fans shows the failure is always in one or more of the 6 Mosfet Transistors on the metal heatsink.
These are labelled SW1-6 in the generic image above.
We currently have two distinct failure modes...
1) If just one of the six power Mosfets fails then the motor may still work to a degree but.....
a) It may not be able to start depending on where the impeller stops. (The fan driver times out after a few seconds if it does not start rotating)
b) It may not reach the correct speed (rpm) due to lack of power from the blown Mosfet section.
(This is why some owners report they can hear it working but still have a fan error code P1448 and no IMA function)
The fan has a speed sensor feedback circuit, and with a certain drive power the MCM expects it to reach certain set speeds (rpm)...
2) If two Mosfets have failed short circuit (allowing current to flow when not commanded)
then this can set up a direct short circuit between the + and - power feeds which immediately blows the under dash fuse 53.
The system is unable to detect this as a fan fault and set code P1448 as the power to the MCM/BCM is lost when the fuse blows.
Conclusions.
If the fuse is immediately blowing and you have no fan related code then it's likely two or more fan Mosfets have failed.
Simply unplug the fan and then replace the fuse to confirm if it is responsible.
If it doesn't blow with the fan unplugged you have the answer.
If you just get P1448, sometimes intermittently and the fuse does not blow, then it's likely one Mosfet has failed or is failing.
Visual detection of which one/s has/have failed is sometimes possible if the Mosfet package has been damaged. (Blown/burnt)
Of course there may be other rare failure modes we haven't encountered yet, but I suspect the above covers 99% of them.
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I wonder what's on the previous page of this thread LOL..
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