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KnuckleBuster76
Active Member

45 Posts

Posted - 04/10/2017 :  04:20:47 AM  Show Profile  Reply with Quote
Lemme lay this one down for ya: 2006 International IC, conventional, juice brakes (for whatever reason), with that goofy driveline park brake unit at the rear axle. Follow me so far? Getting an alarm, ABS and ATC light, but only when it's over 50° ambient air temp. Pulled codes, only thing I got was a stored park brake overtravel code, which should have nothing to do with the lights (problem corrected, btw). I've checked all relays/fuses/plugs. I've cleaned up the battery terminals. I've replaced all electrical components on the park brake unit (solenoid and travel pick-up). I've replaced the brake control box on the firewall near the brake pedal. I've checked all the ABS sensors. I've even replaced the ABS ECU. Scratching my head, here. The "only acts up when it's warm" thing is bugging me. But, even warm, it doesn't act up when I drive it. If you shut off the bus and restart, it'll clear the lights for a time. Any ideas?

drp53188
Senior Member

89 Posts

Posted - 04/10/2017 :  10:32:16 AM  Show Profile  Reply with Quote
If you can get it to act up go into toolbox and open the HABS tab
in the lower left side of the screen note the position of the park brake travel switch, is it matching the park brake? if not ohm out the harness to the ECU if its good replace the SHARS canister.
Had one do this when the temps change, the travel sensor did not see the park brake set but when it got cold again ti woks fine.
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torque
Advanced Member

Canada
358 Posts

Posted - 04/11/2017 :  08:04:17 AM  Show Profile  Reply with Quote
I have seen some mechanics get mixed up, thinking the code is for park brake travel switch, when it is for the switch on the master cylinder. Sometimes brake fluid will seep out and enter the switch. Easy to tell, pull out the switch and see if fluid comes out.
If so, call you dealer with vin as some early switches you can only buy the switch and master assembly. Later ones you can buy just the switch. The switches look close but they are not the same.
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KnuckleBuster76
Active Member

45 Posts

Posted - 04/19/2017 :  04:52:28 AM  Show Profile  Reply with Quote
I think it may have been a driver error. Here's what he said he was doing: "I leave the park brake off, bus in neutral, foot off the brake, and let the tires rest against the curb." A) If that bus is running, your foot is either on the brake or the park brake is set! B) When I told him this the first two times, maybe listen to me? C) Some of these newer buses have the most oddball safety features. For instance, if the electric door is not shut and secured, it'll throw a "service park brake" light when you release the park brake.

"Just... I dunno... Just fix it."
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 04/19/2017 :  04:56:15 AM  Show Profile  Reply with Quote
If I were in engineering at a bus maker, I swear I'd embed some sort of code to make the techs laugh from time to time. Something like "Confused Driver" or something.

In this case, being that hydraulic system, I believe the code I would embed (that would get me fired) would be "Poor Decision"
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KnuckleBuster76
Active Member

45 Posts

Posted - 04/19/2017 :  05:20:26 AM  Show Profile  Reply with Quote
I was thinking a code that reads "Loose Nut Behind the Wheel" or, given the age of most of our drivers, maybe "Auditory Hallucination". If one bus experiences a problem, it seems to follow that several drivers suddenly remember that "Hey, my bus does that too." Funny story that I'm sure is all too familiar: "My step heater just howls, makes all kinds of noise." Ran it for 3 hours, sounded smooth, like a brand new motor. Told the driver it sounded fine and he got beyond irate about it. So, the next morning, after he complained again, I told him I swapped it out with a new motor (while I never actually bothered). He came in, "See? I told you it was making noise. You must've put that new motor in like I told you, because it sounds great!" Overheard him telling other drivers about how much he had to spend to fix his hearing aid earlier in the day. ;)

"Just... I dunno... Just fix it."
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 04/19/2017 :  07:05:53 AM  Show Profile  Reply with Quote
Ah the power of suggestion. I have one driver that we have to do that to sometimes. "Yeah, there was a loose plug under the hood, see if that took care of it...I think that was the issue" Usually it does fix the problem ;)
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eddo
Advanced Member

USA
311 Posts

Posted - 04/19/2017 :  08:45:42 AM  Show Profile  Reply with Quote
I had an old 7.3L IDI that would NEVER fire up on the first try. You could crank and crank and crank- and until you turned the key off and recycled the glow plugs- it would refuse to start. Recycle the glow plugs and it would start right up.

I heard a driver cranking and cranking and cranking this truck one morning, and walked over to the truck. She turned the key off, and hollered at me that it refused to start and she wanted a different truck. I very calmly told her to turn the key back on, I laid my hands on the hood and said some mumbo jumbo rather loudly, and told her to crank it when I heard the glow plug controller clicking. Truck fired right up, I walked off, and her jaw hit the floor.

:)
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KnuckleBuster76
Active Member

45 Posts

Posted - 05/10/2017 :  08:10:15 AM  Show Profile  Reply with Quote
I ended up replacing the ECU. That got it down to one code, revealing an internal HCU leak. Bam! Swapped the HCU, problem solved. Hail to the king.

"Just... I dunno... Just fix it."
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