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P1448 Bad IPU IMA Hybrid Cooling Fan Motor ... Can it be fixed?

17286 Views 41 Replies 8 Participants Last post by  Soulrazy
From evidence on the web and multiple threads on here we can see this IMA fan failure is not uncommon. :cry:

So the $$$ question is can we fix the FAN instead of replacing it? :unsure:

The supply of junk yards fans will likely dry up at sometime and a new one is UK £300.
Cheaper in the US I understand ~$160?

To find out I will need someone to send me a broken one to disassemble for the benefit of the CR-Z community.

Any offers?

The fan failure is often associated with blown IMA 12V fuse 53 which indicates some sort of short circuit.
Is the failure in the motor itself or in the fan drive module attached to it?

We could find out with a dead fan donation.... ;)
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I'm getting the IMA light coming up when battery temps go above 30C and then the IMA fan is running at approx 3700rpm. I pulled code P1448 with the HDS a couple of weeks ago and then it didn't come back as the weather cooled off and battery temps dropped. Well, it is back with a vengeance these past two days, and from reading some other posts it may be that the fan isn't running well on medium speed. Looks like a replacement fan is on the cars and then I might have a broken one to investigate.
I did that right after resetting the codes a couple of weeks ago, which I did as soon as I got home from the trip where the fan was trying to go into orbit. The test ran fine at the time.
I swapped out the fan with a replacement unit I bought from @PeterPerkins, but I am still getting the same fault - battery temps get to 30C, IMA light on and fan speed goes from approx 1700rpm to 3700rpm in response. I've pulled the code and it is still throwing up P1448.

I ran the fan test with the HDS and the fan performs perfectly and meets the test conditions without any issue, so I am currently stumped as to what the actual fault is at this stage. The fan is responding to the speed requests, and the speed is being reported correctly.
The OBDIIC&C is always plugged in and switched on. I've got a trip out tomorrow that should get the battery temps up again, so I'll do it without the OBDIIC&C.
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OBDIIC&C firmware should be OBDIIC&C CRZ +JOY +BAR 150321 V1 (going on my last downloaded firmware). I'll have to double check on the device for sure.

I do have a HDS and I took it out with me today, ready to grab a snapshot if the IMA light came on. As it happens it never did, but it did allow me to workout that the OBDIIC&C does seem to be the issue. My battery temps were just above 30C, no IMA light, and, possibly the most useful bit of info, the IMA fan was not running at this temp. I did notice the IMA fan was running at about 1500rpm when the battery temps rose to around 35C.

I think you have hit the nail on the head with your theory and I was thinking similar on the drive back. The MCM is expecting the fan to be at 0 rpm at 30C, but it is in fact running, so it's teddy out the pram, light on, fan flat out.

I noticed this week when I tried to test the fan speeds via the OBDIIC&C that it doesn't work as expected, and I was sure that when I was first playing around with it last year that it did work as expected. I couldn't get it to run the fan at low speed. Medium and fast were only about a 100-200rpm difference IIRC, up near 4000rpm.
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There is always the risk of unintended consequences when working through things like this. It's all part of the fun.

Thanks for refund, it is appreciated.
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