K75024255
Service Bulletin Details
Public Details for: K75024255
During extended periods of idling, engine speed may increase for a short time without any external command to do so.
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| 9999 MACK CHU |
| 9999 MACK CXU |
| 9999 MACK GU |
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| 9999 MACK TD |
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| 2018 MACK MRU |
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| 2017 MACK LEU |
| 2017 MACK MRU |
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| 2016 MACK LEU |
| 2016 MACK MRU |
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| 2015 MACK LEU |
| 2015 MACK MRU |
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| 2014 MACK MRU |
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| 2013 MACK LEU |
| 2013 MACK MRU |
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| 2012 MACK MRU |
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Models from 2010
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Models from 2009
| 2009 MACK LEU |
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| 2009 MACK TERRAPRO (MRU) |
Models from 2008
| 2008 MACK LEU |
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| 2008 MACK TERRAPRO (MRU) |
Models from 2007
| 2007 MACK LEU |
| 2007 MACK MRU |
Solution K75024255 Tuesday, December 5, 2017 9:02:53 PM CET Solution Title (customer effect) Mack Chassis - Engine Idle Speed Ramps Up To 1100 RPMs With No Driver Input Smart Idle - US10 And Newer Cause During extended periods of idling, engine speed may increase for a short time without any external command to do so. Solution Overview A chassis equipped with a Mack engine will increase engine speed periodically when the truck is idling for an extended amount of time. This is controlled by the Smart Idle function. When the Smart Idle function is active, Low Voltage Fault Protection is also active. System voltage is monitored, and if low voltage is observed, engine speed is automatically commanded to ramp to 1100 RPM for 300 seconds (5 minutes) in order to increase alternator load and recharge the batteries. Repair If the chassis is entering smart idle excessively: 1. Check and confirm that system voltage is not dropping below 12.8 volts DC during extended idle. 2. Load test the batteries. 3. Ensure the alternator is functioning correctly. 4. A voltage drop test may be required if the batteries and alternator are found to be good to determine if there is excessive drain on the system, which may indicate: • A short in a harness or connector • A component drawing excessive power • Too many accessories operating simultaneously • This may include items plugged in in the cab or bunk Interna l comm ents (BO) Smart Idle Parameters, Enabling and Disabling Solution visibility Dealer distribution Function(s)/component(s) affected Function affected engine , battery/power supply , low voltage disconnect , CV electronic control unit , 1 1 0 EMS , MID 128 – EMS , MID 144 – VECU , EECU , VECU , Diagnostic tool Function Group Function Group 2841 Electronic Control Unit , 365 entire vehicle control system Customer effect Main customer effect engine speed , power supply , calibration/programming/pairing/missing operation , diag nostics/methodology Engine speed does not exceed a certain number of revs , unstable idle speed Conditions Vehicle operating mode stationary speed , when stationary Administration Author RU4469V Dealer ID RU4469V Last modified by RU4469V Creation date 03-11-2017 18:11 Date of last update 03-11-2017 18:11 Status Published NA_MACK_Vehicle_Range NA_MACK_Vehicle_Ran ge Engine family Cabover , LR , LEU , MRU , Conventional , CHU , CXU , GU , TD Engine family Mack , MP7 , MP8 , MP10 Emission Standard Emission Standard US17 GHG , US14 CNG , US16 , US15 , US10 , US13 OBD , US14 GHG