[CrzyCRZ]

Not my car ... but my buddy’s 2011 CRZ with 90k miles finally got the death of IPU fan message.


Before the IMA light turns on, there was some strange noise from the trunk area. Within a couple of weeks, the IMA light turned on. I was 95% sure that’s the IPU fan needing to be replaced so my buddy ordered it.

According to multiple threads, it is possible to have the IPU fan covered under the hybrid warranty (15 years / 150k miles warranty in California) and most cases owners only had to pay about $100. My buddy doesn’t want to go through hoop and loops / Honda Headquarter to get it fixed under warranty. He can’t afford the down time of his car.

Symptoms:

- The engine is turned on by the conventional starter by the 12v battery and not the synchronous induction motor by hybrid battery. (Engine Start like a non-hybrid car).

- No hybrid / IMA assist at any RPM.

- 12v battery reads only 10.7v at idling and 12.7v at 2-3k rpm. It’s considered low but the car seems to run fine but battery is draining.

- Turning off the main breaker of the main hybrid battery doesn’t seem to change anything.

- Fuse #53 is burned under steering wheel (you may or may not have this fuse burned)

Tip:

- Assuming the 12v battery is healthy, wait 5-6 seconds at the “On” position before starting the engine. If you turn the key from off to start position too quickly, the conventional starter will not crank over.


Here is a screenshot of the codes:

————————————————————-
Update (9/14/2021):
Quote from Facebook from Richie Poff:

“ … any 06 or newer hybrid Honda’s has the same internals for the IPU fan assembly. The only thing different is the housing the assembly sits in.”

————————————————————-

Update (2/7/2020):

New IPU fan part number:

• 1J810-RTW-003
• A 15A Low-profile Mini fuse

Installation/Removal:

1. Take the spare and foam pieces out
2. Access the right rear plastic panel partially.

3. Loosen the three 10mm bolts on the IPU fan

4. Loosen plastic exhaust tube coming out of the hybrid battery to give you room to to wiggle the IPU fan around. Unplug the IPU fan harness

5. Loosen all the plastic clips around the IPU fans (7-9clips and be careful not to bend those clips too hard). Patience is key.

6. Take out the IPU fan without the exhaust tube

Comparison of old and new to make sure they match:

Old on the left and new on the right:

7. Put in the new fan and connect the harness

8. Replace the burned #53 IMA fuse located near the driver’s knee area (I forgot to replace mine and thought my DC-DC converter was not working). This fuse was burned out to protect the DC-DC converter to operate without a working IPU fan.

9. Disconnect the 12v battery and wait half a minute. I open my doors to discharge any residual power.

10. Reconnect the battery and switch the key to “ON” position (Not starting). Leave it there for at least 10-15 seconds until the system checks itself.

11. Turn on the car and all the messages should be gone. (Both my P1634 and P1448 are gone)

Comments:

If you ever get any of those error codes related to IPU fan or charging system. I highly recommend NOT to drive your car around because you can loose power steering/ABS, risking others on the streets as well as yourself. My buddy was lucky to drive home without power steering. The car pretty much ran really rough without proper 12v charging voltage.

Yes, the hybrid system components should be covered by warranty in CA but my buddy doesn’t want to go thru dealer and do all the explanations.

The IPU fan was 9 years old and the car had less than 90k miles. The fan did make some weird noise

I hope this write up helps and I am not responsible for any damages caused when you replace the fan yourself. Do it at your own risk.

 

[Spdbump]

He should use his warranty but I can understand the not wanting down time. If warranty repair and down time is longer than X some dealers provide loaner car. He should also plan to replace under hood battery due to IMA not working right for X amount of time and it may not recover.

 

[CrzyCRZ]

He should use his warranty but I can understand the not wanting down time. If warranty repair and down time is longer than X some dealers provide loaner car. He should also plan to replace under hood battery due to IMA not working right for X amount of time and it may not recover.

I have discussed with him some pros/ cons using the not-so-guaranteed warranty. He insists on getting it replaced and it’s a part that would eventually fail. He will take the assumption and only bring it to dealer if the IPU fan wasn’t the issue.

The 12v battery is fairly new (a couple years). I can’t stress enough about the importance of the 12v battery to other CRZ owners and I have a load tester at home as well.

 

[Spdbump]

I have discussed with him some pros/ cons using the not-so-guaranteed warranty. He insists on getting it replaced and it’s a part that would eventually fail. He will take the assumption and only bring it to dealer if the IPU fan wasn’t the issue.

The 12v battery is fairly new (a couple years). I can’t stress enough about the importance of the 12v battery to other CRZ owners and I have a load tester at home as well.

But if it is the fan and he uses warranty he is only out time. The other major IMA failure people have posted is a failure of the DC to DC converter. Some dealerships if you do your own work will blame any subsequent failure on what you did and will basically void your warranty.
Even a new battery if discharged too far will not recover due to reversed polarity in one or more cells. But to each their own.

 

[CrzyCRZ]

But if it is the fan and he uses warranty he is only out time. The other major IMA failure people have posted is a failure of the DC to DC converter. Some dealerships if you do your own work will blame any subsequent failure on what you did and will basically void your warranty.
Even a new battery if discharged too far will not recover due to reversed polarity in one or more cells. But to each their own.

The fan is $167 with shipping. The warranty method will cost $100. For $67 more, he could save a couple of days or weeks. That’s one hour of his salary.

Dealer ship will have no idea that I switch the fan. It’s pretty easy to access the fan and I have done it already to direct the hot air from the fan to the side vent. The hybrid battery will not be used for a week so that’s typical vacation time and I think it’s fine.

I will report in after I switch out the fan. If the 12v battery is still low and with the IMA light still on after the fan replacement, then it’s likely to be the dc-dc converter. Right now, the codes that the car gives lead me to believe it’s the IPU fan.

 

[Spdbump]

The fan is $167 with shipping. The warranty method will cost $100. For $67 more, he could save a couple of days or weeks. That’s one hour of his salary.

Dealer ship will have no idea that I switch the fan. It’s pretty easy to access the fan and I have done it already to direct the hot air from the fan to the side vent. The hybrid battery will not be used for a week so that’s typical vacation time and I think it’s fine.

I will report in after I switch out the fan. If the 12v battery is still low and with the IMA light still on after the fan replacement, then it’s likely to be the dc-dc converter. Right now, the codes that the car gives lead me to believe it’s the IPU fan.

I never mentioned hybrid battery only under hood. For my warranty failure the $100 never got charged but what you say makes a lot of sense.
My concern was the misbehaving IMA system damaging the under hood battery.
I hope it is the fan.

 

[litz]

Make sure you trickle charge your 12v battery--as often as every day/night--when you drive your CR-Z without a working IMA system, else you'll have $100+ to fork out for a replacement 12v battery, no matter how new/good current 12v appears to be now. Every system is working to drain it during this time, and nothing to recharge it, destroying its reasonable lifespan.

Otherwise, sounds like a good idea to replace the IMA fan, and see if that alone, solves the problem.

 

[CrzyCRZ]

Make sure you trickle charge your 12v battery--as often as every day/night--when you drive your CR-Z without a working IMA system, else you'll have $100+ to fork out for a replacement 12v battery, no matter how new/good current 12v appears to be now. Every system is working to drain it during this time, and nothing to recharge it, destroying its reasonable lifespan.

Otherwise, sounds like a good idea to replace the IMA fan, and see if that alone, solves the problem.

It’s being trickle charged as we speak. I noticed how low the charging voltage was and decided to charge it when it’s not being used.

One more thing and I will add this to my original post:

The starter won’t crank until I wait at least 5-6 seconds. My friend thought the 12v was dead but I guess the system takes a few seconds to recognize that it needs to use the conventional starter to crank the engine...

 

[CrzyCRZ]

I never mentioned hybrid battery only under hood. For my warranty failure the $100 never got charged but what you say makes a lot of sense.
My concern was the misbehaving IMA system damaging the under hood battery.
I hope it is the fan.

Sorry I misread. I have the same fear about the IMA system not properly charging the underhood battery. I hope a week of abnormal charging won’t damage any components of the system.

Cross my fingers !

 

[Spdbump]

@litz is right put it on a trickle charger till issue resolved and carry a jump box.

Sorry I misread. I have the same fear about the IMA system not properly charging the underhood battery. I hope a week of abnormal charging won’t damage any components of the system.

Cross my fingers !

 

[CrzyCRZ]

I have updated my original post and the new IPU fan fixed the problem along with a fuse replacement.

 

[d1giPhux]

How full of dust was the fan when you pulled it? I need to remember to pull mine and clean it soon, as I know in my area.. it probably full of crap!

 

[CrzyCRZ]

How full of dust was the fan when you pulled it? I need to remember to pull mine and clean it soon, as I know in my area.. it probably full of crap!

It wasn’t that dusty at all. There’s a circuit board with inductor, capacitors, and other electronic components. It could be one of those or the fan motor fried...

I have pulled mine (2014) out for cleaning and also added a flexible tube to channel the hot exhaust air to the side body vent....

 

[d1giPhux]

@CrzyCRZ : Do you think that tube does anything in terms of cooling? I would be worried that it would interfere with the cooling, as you would think they would have tested how well the cooling works at factory. How has it worked out for you?

 

[CrzyCRZ]

@CrzyCRZ : Do you think that tube does anything in terms of cooling? I would be worried that it would interfere with the cooling, as you would think they would have tested how well the cooling works at factory. How has it worked out for you?

I used to hear the fan spooling up but now I don’t hear it anymore. The purpose of my tube is to direct the hot air straight to the vent and out of the car instead of having the hot air hanging out in the trunk area. The exhaust of the fan literally points towards the spare tire from factory

 

[d1giPhux]

@CrzyCRZ : oh NICE!! I gotcha now. This does look like a good mod!! Very cool. What did you use, just some flexible dryer tube type stuff? And it doesn't get pinched at all? Very cool!! (literally too)

 

[CrzyCRZ]

@CrzyCRZ : oh NICE!! I gotcha now. This does look like a good mod!! Very cool. What did you use, just some flexible dryer tube type stuff? And it doesn't get pinched at all? Very cool!! (literally too)

Thanks !

Here’s a link to the amazon page:

Hon&Guan 3 inch Air Duct - 16 FT Long, White Flexible Ducting HVAC Ventilation Air Hose For Grow Tents, Dryer Rooms,Kitchen Hon&Guan 3 inch Air Duct - 16 FT Long, White Flexible Ducting HVAC Ventilation Air Hose For Grow Tents, Dryer Rooms, Kitchen - - Amazon.com

You can use any duct. I did have to pinch the duct a little but still plenty of room for the hot air to come to the side body vent.

 

[MrFastFox666]

My concern was the misbehaving IMA system damaging the under hood battery.
I hope it is the fan.

Make sure you trickle charge your 12v battery--as often as every day/night--when you drive your CR-Z without a working IMA system, else you'll have $100+ to fork out for a replacement 12v battery, no matter how new/good current 12v appears to be now. Every system is working to drain it during this time, and nothing to recharge it, destroying its reasonable lifespan.

The 12v battery in most cars, including the CR-Z, is an SLI battery. These are built to give high current, but the sacrifice is that they suffer a lot when discharged, even just a bit. 10 cycles might be enough to kill an SLI battery. Thats why leaving the headlights on is such a big deal.

I'd bet that the battery suffered a lot when you drove the car without IMA, and I'm sure it'll fail prematurely. If you haven't, I recommend you get it load tested.

 

[Spdbump]

Or if you have the money just replace it!

The 12v battery in most cars, including the CR-Z, is an SLI battery. These are built to give high current, but the sacrifice is that they suffer a lot when discharged, even just a bit. 10 cycles might be enough to kill an SLI battery. Thats why leaving the headlights on is such a big deal.

I'd bet that the battery suffered a lot when you drove the car without IMA, and I'm sure it'll fail prematurely. If you haven't, I recommend you get it load tested.

 

[CrzyCRZ]

The 12v battery in most cars, including the CR-Z, is an SLI battery. These are built to give high current, but the sacrifice is that they suffer a lot when discharged, even just a bit. 10 cycles might be enough to kill an SLI battery. Thats why leaving the headlights on is such a big deal.

I'd bet that the battery suffered a lot when you drove the car without IMA, and I'm sure it'll fail prematurely. If you haven't, I recommend you get it load tested.

I have a battery load tester at home. I have four cars at home and do quick checks from time to time.