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Discussion Starter #1
Hello All.

I am new to this forum, but also pretty new to forums overall, so I apologize in advance for breaches of etiquette I am sure to commit.

I joined specifically because I am having problems with my 2008 Veracruz. Since buying it used about 4 years ago, we have been having problems with the brakes. Specifically there is some shuddering in the pedal and the car overall when braking at low speeds - typically between 25 and 15 mph.

A few years ago I saw some internet posts about a recall done on brake light switches, so I contacted the dealer in our area and had them replace the switches, despite being notified that they had already been replaced by a previous owner. At the time we were also experiencing issues with the ignition not turning and the shifter getting stuck. Replacing the switches resolved the ignition issues, but did nothing about the (I presume) inappropriate engagement of the ABS. The dealer would not honor the recall on the switch, and we were charged for the replacement, to my frustration, since it clearly was a faulty switch causing at least the shifter issues.

It's been a few years now though, and it is getting a little more consistent, and the braking seems worse overall. We took it to a brake shop here, and they did one last machining on the discs and replaced the pads - but this did not help, and recently we finally got some lights on the dashboard - ABS, ESB and Emergency Brake I think. They pulled a code or two, and told us the HECU will need to be replaced - this will be in the 2k plus range, and that's getting a little hard to justify for a car this age and mileage, but I would do it, if I felt confident that the suggested repair would actually resolve these issues.

I've done a little more searching, and I have seen a number of complaints from people who have replaced this and not seen issues resolved. So, finally, my question for users who have experience - did Hyundai ever get this part of the vehicle line fixed? Will a repair of the HECU likely resolve problems, or simply be another step in chasing a gremlin which appears to haunt these cars?

Any feedback would be greatly appreciated. Thanks!
 

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Need the codes.
 

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Of course! I actually didn't think to ask the mechanic who looked at it, but I will call them tomorrow and see if they still have it somewhere. He did give me a print out of General Information related to "C1604 ECU Hardware Error." Presumably that was one of them, if not the only one found. I'll try to have a more concrete answer tomorrow. Thanks so much for taking the time to look and reply!
 

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Of course! I actually didn't think to ask the mechanic who looked at it, but I will call them tomorrow and see if they still have it somewhere. He did give me a print out of General Information related to "C1604 ECU Hardware Error." Presumably that was one of them, if not the only one found. I'll try to have a more concrete answer tomorrow. Thanks so much for taking the time to look and reply!
That code is for an internal fault with the module. The unit will need to be rebuilt or replaced if you want it to work properly. I don't believe the unit is causing your braking issue as it should not be doing anything as long as it's failed. The system should work as a typical braking system.
 

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That code is for an internal fault with the module. The unit will need to be rebuilt or replaced if you want it to work properly. I don't believe the unit is causing your braking issue as it should not be doing anything as long as it's failed. The system should work as a typical braking system.
Have you heard about people having the same braking issues where it appears that the anti-skid engages inappropriately? Is it possible that these codes and the one time light-up on the dash were just a one-off and the underlying problem is separate then? The brake problems definitely predate the lights going off and have been pretty consistent.
 

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Have you heard about people having the same braking issues where it appears that the anti-skid engages inappropriately? Is it possible that these codes and the one time light-up on the dash were just a one-off and the underlying problem is separate then? The brake problems definitely predate the lights going off and have been pretty consistent.
Pull the fuse for the module. If it's not able to activate any solenoids it should not impact the braking. If it still has an issue it's going to be something in the system OTHER than the module.
 

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Pull the fuse for the module. If it's not able to activate any solenoids it should not impact the braking. If it still has an issue it's going to be something in the system OTHER than the module.
Thanks - I just want to be sure I have your advice here correct. I identify the fuse which should be for the HECU, yank it, and see if when I press the brakes the solenoids in the HECU engage? Is this something I will be able to hear without exposing the HECU?

Regardless, after pulling the fuse, the HECU shouldn't be doing anything, but the car should be safe enough to drive a little, and if the problem persists, then I can rule out the HECU. Is this correct?
 

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Thanks - I just want to be sure I have your advice here correct. I identify the fuse which should be for the HECU, yank it, and see if when I press the brakes the solenoids in the HECU engage? Is this something I will be able to hear without exposing the HECU?



When you pull the fuse the unit will not work. That's what we want. No solenoids will operate. The brakes should work like a car without ABS.


Regardless, after pulling the fuse, the HECU shouldn't be doing anything, but the car should be safe enough to drive a little,



Drive it a lot....the brakes are made to work even if the module is not working.



and if the problem persists, then I can rule out the HECU. Is this correct?


Yes
...
 

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Specifically there is some shuddering in the pedal and the car overall when braking at low speeds - typically between 25 and 15 mph.... inappropriate engagement of the ABS.
This sounds like the symptoms of a cracked ABS tone wheel, where the ABS will activate as your slowing down under light braking. That causes the brake pedal to vibrate and is often accompanied with a kind of grinding noise which is the ABS solenoids being rapidly switched on and off.

I'd certainly suggest you have the four tone wheels carefully inspected for cracks before replacing the expensive HECU.

 

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This sounds like the symptoms of a cracked ABS tone wheel, where the ABS will activate as your slowing down under light braking. That causes the brake pedal to vibrate and is often accompanied with a kind of grinding noise which is the ABS solenoids being rapidly switched on and off.

I'd certainly suggest you have the four tone wheels carefully inspected for cracks before replacing the expensive HECU.

Thank you! This seems a very promising lead. Without divulging too much personal info, I just had back surgery, so I am relying entirely on a shop for what I would normally have tried to tackle on my own. I had never heard of a Tone Wheel before, but I would have guessed that a shop purporting to be a brake specialist would have. However, they were surprised by my request that they take a look at the Tone Wheel before replacing the HECU, and I got the impression that they didn't know what a Tone Wheel was (though I guess I could be wrong).

In short, should this concern me? Should I take the car somewhere else, or are Tone Wheels something a little specific to Hyundai ABS systems and not well known outside of Hyundai specialists (of which there are few if any in Tucson)?

Thanks again for the lead!
 

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Thanks! This makes a ton of sense. As I just replied in another post, I'm not doing much work on my own right now. The shop I took it to said they think the mechanic working on my car did pull the fuse as part of his testing process, but I'm not supremely confident they did, and would like to double check on my own. But when I looked up the list of fuses for a VC, there appeared to be several related to ABS and ESC. Could you perhaps help me to pinpoint which fuse or fuses to pull to disable the HECU? I didn't see one specifically referencing it.

Thanks again for all your help in this!
 

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Thanks! This makes a ton of sense. As I just replied in another post, I'm not doing much work on my own right now. The shop I took it to said they think the mechanic working on my car did pull the fuse as part of his testing process, but I'm not supremely confident they did, and would like to double check on my own. But when I looked up the list of fuses for a VC, there appeared to be several related to ABS and ESC. Could you perhaps help me to pinpoint which fuse or fuses to pull to disable the HECU? I didn't see one specifically referencing it.

Thanks again for all your help in this!
Just pull the connectors off the module.
 
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