2020 Peterbilt 520 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."

engines.

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.

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.

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

The absence of this valve could affect rear brake timing on certain vehicles equipped with a tri-drive or liftable tag axle and Dual Seated or Right Hand Stand-Up steering configurations. Vehicles will be inspected and, if necessary, a QR valve will be installed.

exist in certain Model 520 vehicles built from 9/26/2019 through 7/22/2020 with stability control and a spring brake modulator valve (SBM) or lift axle. The Stability Control Relay may have been plumbed incorrectly, which could cause a stability event that may actuate the lift axle brakes or modulate the park brake chambers, which could destabilize the vehicle. This bulletin will be updated as soon as an affected chassis list is defined and a repair procedure is developed.

December 20, 2019 may have incorrect steering assist cylinder bracket bolts installed, which prevents proper retention of these bolts.The steering assist cylinder bracket attached to the right front spring bracket with these bolts may also be damaged. The bolts installed may not have the required thread lock and this could result in loose or missing hardware. This may cause the bracket to flex or break and cause damage to adjacent components or lock up steering. Resolution is to remove and reinstall the steering gear assist bracket bolts with thread locker.

have been built without a quick release valve. The absence of this valve could affect rear brake timing on certain vehicles equipped with a tri-drive or liftable tag axle and Dual Seated or Right Hand Stand-Up steering configurations. Resolutoin is to inspect for a quick release valve installed, and if there is not one, to install a quick release valve.

certain Model 520 vehicles with Right Hand Stand Up (RHSU) configuration built between June 15, 2018 and February 14, 2019. Vehicles may have an improperly supported steering gear assist bracket due to the incorrect spring bracket installed. The spring bracket may be missing 3 drilled and tapped holes which will provide additional support for the steering gear assist bracket. An improperly supported steering gear assist cylinder bracket may break and cause damage to surrounding components and/or lock up the steering, increasing the risk of a crash. Resolution is to inspect and verify the steering assist bracket is installed with 5 required bolts. If 5 bolts are not installed, a new bracket will be installed.

vehicle safety, may exist in certain Model 520 vehicles with Right Hand Stand Up (RHSU) configuration built between June 15, 2018 and February 14, 2019. Vehicles may have an improperly supported steering gear assist bracket due to the incorrect spring bracket installed. The spring bracket may be missing 3 drilled and tapped holes which will provide additional support for the steering gear assist bracket. An improperly supported steering gear assist bracket may flex or break and cause damage to other components or cause the steering to lock up. This bulletin will be updated as soon as parts become available for the repair.

in certain model 348, 367, 389, 520 or 567 vehicles manufactured between November 22, 2019 and December 5, 2019. Output shafts may not have been correctly heat-treated and could break near the pinion nut. Resolution is to inspect the driveshaft to verify the julian date, and if witin th esupect date rate,, replace the output shaft.

Brass fittings are available to replace the composite fittings.

vehicle safety, exists in certain model year 2017, 2018, 2019 and 2020 Model 520 vehicles manufactured between October 17, 2016 and March 04, 2019 with left hand or right hand single steer Power Distribution Center (PDC) harnesses. The power wire to the PDC may be inadequate and unable to accommodate the current draw. This can cause the wire to overheat and potentially melt the cab power harness connector. This could cause a loss of power to the cab and engine, which may result in the engine shutting down. A sudden loss of engine power could increase the risk of a crash.

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.

for a retrofit of the digital display to a production intent unit that features updated base software, secured hardware, and the ability to be updated with software released after February 2021.

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.

rails may leak around a sealing washer, potentially resulting in fuel leaks.Undetected prolonged diesel fuel spray in the presence of an ignition source may increase the risk of fire.

The presence of the wire could result in a false fault code.

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.

may have been equipped with a Main Cab Harness that enables the Door Alarm to sound when it should be disabled. Model 520 vehicles with this configuration should have the door alarm disabled when the passenger door is open and the vehicle is in drive mode.

required with current architecture. If left in place, a fault code P1644 may be set.

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."

Revised hardware will resolve the leak.

Torque specifications for these fasteners are different from previous fasteners.

Reference the procedure in the attachment section to properly remove and replace the insulation.

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

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

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

service port spacing which will not allow the connection of a pressure gauge to both the high and low side service ports simultaneously. A specific tool is available from the supplier that will allow a technician to bypass this design issue.

A/C compressor.

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

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.

vehicles built between 11/19/2019 and 4/09/2020. Vehicles equipped with Watson & Chalin SL2065 lift axles may have lower rear pivot bolts that are not long enough to sufficiently engage the locking feature of the corresponding nuts. In some cases, this condition may cause a loss of clamp load of the pivot joint (arm to axle). Extended use of the lift axle in this condition can result in foreign object debris on the roadway, increasing the risk of a crash and/or injury.

Vehicles were equipped with additional amber stop lamps which may illuminate when the brake is applied, and may confuse other drivers. Resolution is to remove the amber stop lamps and associated wiring.

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.