2012 Mustang - How to put hcu back on abs housing?

kreeze

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I screwed up. I'm getting a C1A99:17-8B code on my 2012 V6 automatic. I've replaced the abs module once before with a used part when I was getting a similar code (don't remember if it was this exact code). I figured maybe that part died again, so I ordered another one and installed it. Lo and behold that did not fix the issue. In doing further research I found this thread (https://www.s197forum.com/threads/a...e-the-module-pass1over-do-it-some-tim.141367/) which noted that the fix was to replace the hcu. The used abs module I bought also came with the hcu, so I figured I'd be smart and just take the actual sensor off and replace that. Well, I don't know what magic tool Ford used to put this sensor on the block, but I don't have it.

There are two pins held in tension by springs on both sides of the slot the hcu sensor goes in. You have to somehow slide those pins back while putting the sensor back on the block and then also be able to remove whatever tool you used to fully seat it. How in the world can I get this back on the block? Am I SOL? Do I just need to buy another one and disconnect the brake lines and bleed the brakes like I was avoiding?

Also, please let me know if I'm not using the correct names for the parts in the pictures below. I'm unsure which specific part is the HCU and which is the pump. Did I take the pump off the HCU?

IMG_20250914_202601.jpgIMG_20250914_202609.jpgIMG_20250914_202659.jpg
IMG_20250914_202719.jpg
 
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nyuk98GT

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kreeze,

The vertical pin in the HCU reminds me of the rotor in an electric motor and the horizontal pins reminds me of the brushes. Not sure if you tried this but won't the vertical pin on the HSU push the two horizontal pins if the HCU is pushed in with some gusto? If you can move one of the horizontal pins with your finger, then the HCU should be seatable.

The other thing I noticed is the sealed plug on the side of the lower housing that lines up with the horizontal pin. Not sure if it is wise to remove that plug or if it can be removed without some special tool.

Have you looked on YouTube? I did a quick look but didn't see any for HCU surgery.

HTH,

Chris
 

Forty61

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That looks like an utter nightmare to get back together.. how strong are the springs behind those two pins?
 

kreeze

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@nyuk98GT--believe me, I tried with gusto and unfortunately it does not seat that way. I was also not able to find a way to remove the sealed plug you mentioned.

@Forty61--I agree. Total nightmare! The springs are about as strong as you can imagine for that size.

I ended up just buying another one... Lesson learned. Don't take stuff apart without researching it! Luckily the replacement resolved my issues. I did have to use FORScan to update the ASBuilt data of the ABS module to match the VIN.
 

nyuk98GT

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kreeze,

Thanks for the update. I lol-ed that you applied gusto to your installation effort. Sometimes it works (and the part doesn't break but not this time).

Very glad to hear that the full replacement (and some FORScan skills) got you in tall corn.
Enjoy the Mustang now!

Chris
 

cloud51ve

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I screwed up. I'm getting a C1A99:17-8B code on my 2012 V6 automatic. I've replaced the abs module once before with a used part when I was getting a similar code (don't remember if it was this exact code). I figured maybe that part died again, so I ordered another one and installed it. Lo and behold that did not fix the issue. In doing further research I found this thread (https://www.s197forum.com/threads/a...e-the-module-pass1over-do-it-some-tim.141367/) which noted that the fix was to replace the hcu. The used abs module I bought also came with the hcu, so I figured I'd be smart and just take the actual sensor off and replace that. Well, I don't know what magic tool Ford used to put this sensor on the block, but I don't have it.

There are two pins held in tension by springs on both sides of the slot the hcu sensor goes in. You have to somehow slide those pins back while putting the sensor back on the block and then also be able to remove whatever tool you used to fully seat it. How in the world can I get this back on the block? Am I SOL? Do I just need to buy another one and disconnect the brake lines and bleed the brakes like I was avoiding?

Also, please let me know if I'm not using the correct names for the parts in the pictures below. I'm unsure which specific part is the HCU and which is the pump. Did I take the pump off the HCU?

View attachment 110563View attachment 110564View attachment 110565
View attachment 110566
The front housing of the module comes off and goes on pretty easily. I think that is how you would avoid bending those pins. I only know because I took it off to replace the Brake Pressure Sensor. Here's a link to the post about that process and a video that shows me taking off the module. https://www.s197forum.com/threads/c1a99-17-8b-brake-pressure-sensor-replacement.153924/

Edit:

It was actually to fix that code: C1A99:17-8B
 
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