2020 Peterbilt 579 TSBs

This update provides customers with additional time to service their trucks before a DEF-related derate occurs. The software is being offered to customers in alignment with recently updated regulatory agency guidance.

This update provides customers with additional time to service theirtrucks before a DEF-related derate occurs. The software is being offered to customers in alignment withrecently updated regulatory agency guidance."

crank-mounted fan drive may experience a short due to chafing or water ingress, affecting fan drive operation.

engines.

system inspection process for all engine air intake system components.

When troubleshooting Cummins X15 fault codes 555 or 556, follow this additional testing, inspection, and documentation procedure to help identify the root cause of dusted engines. This is not a stand-alone process but must be used alongside Cummins troubleshooting steps. Cummins Quickserve will reference this bulletin for fault codes 555 or 556.

A new Starter Troubleshooting Guide has been created to provide a comprehensive list of starting system checks, which should reduce unnecessary starter replacements and associated warranty claims. Engine starting system warranty claims now require a completed Starter Checklist, a Battery Pack Midtronics Report, and a Cable Drop Midtronics Report. Claims filed without these documents may be denied.

With full suspension articulation, HCV bracket flexes and toggles over center the HCV linkage, which results in either deflated airbags or makes them unable to inflate. Fix-as-fail start date is 07/30/2024.

application and/or under torqued and could become loose and/or fail. Procedures are available to replace and properly torque the hardware.

Broken oil valve tabs can cause oil flow obstruction to critical engine parts, resulting in serious engine damage. Customers that do not receive this repair may be responsible for progressive engine damage caused by broken oil bypass valve tabs.

Cummins X15, X12, ISX12, ISX12N, L9N, PX-7, and PX-9 engines The technology will leverage the existing Remote Diagnostic cs hardware to deliver secure software updates remotely. This will reduce downtime and save on maintenance costs for eligible vehicles.

(HCV) arm may be rubbing on other components when the bend in the arm is facing outboard. Flipping the bend in the HCV arm inboard prevents the rub.

weather.

The Turbo Inlet Elbow will be replaced with an improved part.

PACCAR MX-11 and MX-13 EPA 2021 Emissions engines. Production-level components are now available to make these vehicles compliant.

and/or 3838 due to fan speed that results in the fan remaining activated until the power is cycled. A new controller will resolve the issue.

Crossmember mounted Hill Start Assist valve may not have sufficient clearance to the rear axle, resulting in hose or fitting damage. Damage could cause the loss of rear brake signal, resulting in reduced braking capability and increasing the risk of a crash.

Cummins Recall C2402.

A defect, which relates to motor vehicle safety, may exist in certain Model 365, 389, 567, and 579 vehicles manufactured between April 18, 2014 and March 09, 2020 with a left-hand under hood jumper start terminal. Jumper terminal battery cables may be too long, or eligible for improved routing. Battery cables that are too long may chafe against the left front suspension leaf spring, which could cause a short circuit, fire under the hood, or increased risk of crash. "

certain Model 365, 389, 567, and 579 vehicles manufactured between April 18, 2014 and September 30, 2019 with a left-hand under hood jumper start terminal. Your vehicle may have jumper terminal battery cables that are too long, or are eligible for improved routing. Battery cables that are too long may chafe against the left front suspension leaf spring, which could cause a short circuit, fire under the hood, or increased risk of crash.

Brass fittings are available to replace the composite fittings.

in certain model year 2020 Model 567 and 579 vehicles manufactured between 2/15/2019 and 3/15/2019. The upper mirror in the side mirror assemblies could fall from the housing and limit the visibility of the driver. The mirror and carrier will be inspected to verify the Mekra Lang manufacture date and replaced if necessary.

control unit (VECU2) and digital display (DD). Steps have also been added to the PACCAR Common Rail Injection 2 (PCI2) software verification.

to provide general use information. The new EMUX Service Tool Kit improves cab & chassis electrical troubleshooting efficiency, while reducing risk of component damage. 4/29/2025: The Ethernet Multiplexed Architecture (EMUX) Service Tool Kit and individual kit components are now available to order. Dealers that have received their first kit may order an additional kit. The EMUX Service Tool Kit Part number has been updated to match OEM drawings (P74-1045-001). Individual kit component part numbers can be found in the Reference Bill of Materials sheet. The new EMUX Service Tool Kit improves cab & chassis electrical troubleshooting efficiency, while reducing risk of component damage. Information Only New diagnostic tool is required to support PACCAR Ethernet Multiplexed Architecture (EMUX). The EMUX Service Tool Kit will help improve cab & chassis electrical troubleshooting efficiency, while reducing the risk of component damage.

This software update corrects or improves certain functions. Software update procedures have been revised. Campaign start date is 12/05/2024. Campaign A software update is available for 520EV and 579EV Battery Electric Vehicles. This software update corrects or improves certain functions. Campaign start date is 12/05/2024.

The EMUX Service Tool Kit will help improve cab & chassis electrical troubleshooting efficiency, while reducing the risk of component damage.

Vehicles.

Pressure Sensors for MX-13 -2, EMY19 Per Environment and Climate Change Canada (ECCC) regulations and guidance (Canadian Environmental Protection Act, 1999 (CEPA)), a letter has been provided to owners of Canadian registered chassis that provides a list of emissions components that have been reported (to ECCC) as having a defect.

causing possible damage.

chafing of the battery cables.

Reinforcement brackets secure the connection and prevent separation.

As a temporary solution, after PACCAR confirms a DEF sensor is not available, a temporary software update will allow a vehicle to continue operation with a failed DEF sensor by disabling the DEF sensor diagnostics.

right-hand side.

A VECU software update is available to resolve the issue.

Updated VECU software is available to resolve the issue.

appropriate tests for battery warranty are performed in order to prevent battery warranty claims filed with incorrect or incomplete information.

03/6/2006 to 1/20/2020, the clamps that secure the SOC exhaust stacks may not be tightened properly. This may allow the exhaust stack to rotate and contact the cab or sleeper.

to repeated door open and close cycles. Resolution is to replace the door harness with a more robust designed harness if a failure is experienced.

model 579 or 567 chassis equipped with a VECU software version 9.8 and 9.9. The issue will be fixed on a future VECU software update. This bulletin will be updated when the resolution is available.

Espar fuel fire heater and SmartAir may have an auto On/Off malfunction at lower temperatures. User may experience lack of heat function on SmartAir if the set temperature is < 76 F. Resolution is to install a jumper harness.

Espar fuel fire heater and SmartAir may have temperature overshoot issue. User may experience higher sleeper interior temperature than the set temperature on the SmartAir control. Resolution is to install an additional external temperature sensor on the sleeper control panel.

A procedure for installing a V-CAN overlay will correct this issue.

A battery box closeout has been designed and when installed will prevent debris from entering the battery box.

housings.

left-hand or right-hand blind spotters, may set false Diagnostic Trouble Codes (DTC) 522490-9 or 522491-9. These DTCs can be ignored if corresponding blind spotter is not equipped. The next Digital Vision System Mirrors (DVS-M) software update will correct these false DTCs.

may experience bracket failure causing the bracket and camera to fall from the windshield.

fatigue from external forces such as reverse towing.

fender and the bottom of the trailer/equipment are susceptible to damage. The lack of clearance could result in cracked/broken quarter fenders or complete separation if undetected or un-remedied.

Washer pumps may fail to spray due to a clogged filter.

Vehicles built from 9/27/2019 through 2/06/2020 with windshield Julian date codes between 263 of 2019 and 031 of 2020 could be affected. Resolution is to replace any failed windshields with a delaminated seal.

latest prognostics bulletin verbiage.

The bulletin will be updated when more information is available."

This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.

Service Information Record (SIR) at the time of RO open date to qualify. Also, Through Standard Warranty or any applicable active Extended Warranty verbiage was removed from Warranty section.

Recommended Repair T016C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25-17A for 6.9 hours created to replace all other codes. 26-040: Warranty section updated to include 0.5 hours for test drive. Recommended Repair 26040C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25-17A for 6.9 hours created to replace all other codes.

The issue can be temporarily resolved using any one of the included procedures.

Oil from the air shift cover of the PTO may leak into the air line, causing the EOA solenoid to become inoperative.

Premature Main Drive Gear damage may occur due to clutch housing and main case countershaft bearing bore wear.

and main case countershaft bearing bore wear. A Clutch Housing Front Cover Kit will be installed to address the issue.

Software flash resolves issue.

(LCA) fault codes leading to possible LCA hardware replacement.

lamp activation, no gear engagement from neutral, and/or DTC 511 FMI 7 or 10 is set. Resolution is to update the transmission software and calibrations.

codes leading to possible LCA hardware replacement.

5/01/2017 and 4/07/2019, may have a fluid pressure sensor rubbing or experiencing hard interference with routing brackets, power cables, wiring harnesses, or air lines in the drivers side frame rail.

steering fluid loss.

2 chassis added to the chassis list. Peterbilt: Dealers should check the chassis list and SIR weekly for VIN changes. 10 chassis added to the chassis list."

midship one-piece aluminum crossmembers.

Torque specifications for these fasteners are different from previous fasteners.

Total chassis population is 732.

Inspection Program (PSIP) and Heavy Duty Vehicle Inspection Program (HDVIP).

The HVAC may intermittently stop blowing cold air, typically after a truck restart. Driver may notice the system returns to normal after key cycle. The remedy is updating HVAC software.

A/C compressor.

changes in fan speed that can be remedied with an updated HVAC software.

The work brake (also known as winch brake) may unintentionally disengage during winching operations, releasing the service brakes, increasing the risk of crash or injury. The VECU software will be updated to correctly set the speed interlock parameter.

Meritor brake chambers were built with a misaligned park spring, which may cause a fatigue hole in the diaphragm and an internal air leak. The affected brake chambers will be replaced.

trucks, built between 4/13/2010 and 3/16/2020 and equipped with a flush mounted battery box, utilized rubber washers that could rub through and cause the aluminum box mounting tabs to rub directly on the steel frame brackets. This could result in cracked battery box mounting angles. Resolution is to add the reinforcement bracket(s) to affected vehicles.

MUX switches, and Kick Panel.

A software update is available to resolve this issue.

the headlamps, fog lamps or turn signals are not on. This is non-compliant with Canadian Regulation CMVSS 108, which states that the DRLs must be on while the vehicle is in motion without certain other lamps being activated. This bulletin will be updated when a repair is available.

January 01, 2017 and July 06, 2020. Torsional vibration may stress the currently-installed brackets and cause them to fail near the bottom of the frame rail.

On certain trucks, the reflective conspicuity tape on the back wall of the sleeper box was installed in incorrect locations. FMVSS 108 Section S8 2.4.2 regulations require the conspicuity tape to be placed in specific areas. A truck that does not have properly placed conspicuity tape may be less visible to others and could create an increased risk of a crash. Vehicles operating without a trailer may be cited for incorrect tape location and fail an annual truck inspection. REsolution is to inspect the location of the back of sleeper reflective tape, and apply in the proper location if required.

Gateway (PMG001) will experience severe 3G service degradation as early as January of 2022. Chassis currently utilizing 3G antennas as a primary antenna may experience this degradation.

A redesigned bracket can be purchased that relocates the marker bracket to the front fuel tank bracket to eliminate interference.

The driver could be unaware of an issue with the methane detection system or excessive methane present, increasing the risk of a fire, crash and/or personal injury. The repair procedure will be added when it is available.

built between March 27, 2012 and January 20, 2019 with Flex Air suspension in a 6x2 configuration have U-bolts that may fail prematurely.