2020 Peterbilt 520 problems, complaints & recalls
Most-reported problem areas: Service Brakes (3)
Safety recalls (12)
Suspension:multiple Axle 2022-12-16 · campaign 22V939000 · 15,658 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2015-2023 Peterbilt 320 and 520 refuse trucks equipped with Haulmaax/EX suspensions. The suspension tracking rod brackets may fail and detach from the forward drive axle, causing the axle to become unstable.
Risk: An unstable axle can decrease vehicle stability and control, increasing the risk of a crash.
Fix: Dealers will inspect the welds and add an additional bracket between the tracking rod bracket and axle housing, as necessary, free of charge. Owner notification letters are expected to be mailed February 14, 2023. Owners may contact Peterbilt's customer service at 1-940-591-4220. PACCAR's number for this recall is 22PBL.
Steering:critical Fasteners 2022-04-25 · campaign 22V277000 · 17,641 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2018-2020 Kenworth T270, T370, T440, T470, T660, T680, T880, T800, W900, W990; and 2018-2020 Peterbilt 330, 337, 348, 365, 367, 389, 520, 567, and 579 vehicles. The Dana D-Series axle steer arm fasteners that attach the steering arm to the steering knuckle may fail.
Risk: Fastener failure can result in a loss of steering control, increasing the risk of a crash or injury.
Fix: Dealers will replace and torque the steer arm fasteners, at no charge. Owner notification letters were mailed November 8, 2022. Owners may contact Kenworth customer service at 1-425-828-5888 and Peterbilt customer service at 1-940-591-4220. PACCAR's numbers for this recall are 22 PBB and 22 KWB.
Service Brakes, Air 2021-09-16 · campaign 21V720000 · 15 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2020-2021 Peterbilt 520 vehicles. The quick release valve on the rear brake signal hose may be missing. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 121, "Air Brake Systems."
Risk: A missing quick release valve cannot ensure correct rear brake release timing, increasing the risk of a crash or injury.
Fix: Dealers will inspect the vehicles for a missing quick release valve, and install one if necessary, free of charge. Owner notification letters were mailed on October 7, 2021. Owners may contact PACCAR's customer service at 1-940-591-4220 (Peterbilt). PACCAR's number for this recall is 21PBK.
Fuel System, Diesel:fuel Injection System:fuel Rail 2021-05-26 · campaign 21V391000 · 612 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2018-2021 Peterbilt 337, 348, 365, 367, 520, 567, Kenworth T270, T370, T440, T470, T800 and T880 vehicles. The sealing washer may not seat correctly in the pilot bore holes, allowing the high pressure fuel rail assembly to leak.
Risk: A fuel leak in the presence of an ignition source increases the risk of a fire.
Fix: Dealers will inspect the rail threads and fuel lines, and replace the rail as necessary, free of charge. Owners may contact PACCAR customer service at 1-425-828-5888 (Kenworth) or 1-940-591-4220 (Peterbilt). PACCAR's numbers for this recall are 21KWC and 21PBD.
Steering:column 2021-01-11 · campaign 21V004000 · 1,021 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2015-2021 Peterbilt 320 and 520 vehicles. The steering column support structure may crack or break in certain right-hand, stand-up drive models.
Risk: If the steering column loosens from the mounting structure, steering control can become affected, increasing the risk of a crash.
Fix: PACCAR will notify owners, and dealers will inspect the 520 models right hand stand-pp steering column structure and replace it if cracks are present, as well as add additional support brackets to the new (if replaced) or existing structure, free of charge. Additionally, for the 520 models, dealers will install a large gusset with triangulating support for the column bracket, free of charge. Owner notification letters were mailed July 30, 2021. Owners may contact Peterbilt customer service at
Electronic Stability Control (Esc) 2020-11-25 · campaign 20V739000 · 11 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2020-2021 Peterbilt 520 vehicles. The stability control brake relay may have the Spring Brake Modulating (SBM) Valve or the lift axle hose incorrectly connected.
Risk: A stability control event meant to only actuate the ABS controlled wheel ends could actuate lift axle brakes or modulate park brake chambers and could possibly de-stabilize the vehicle, increasing the risk of a crash.
Fix: PACCAR will notify owners, and dealers will inspect the suspect chassis and correct the brake relay plumbing if needed, free of charge. PACCAR has issued owners an interim notification on January 4, 2020. Owner notification letters were mailed on January 25, 2021. Owners may contact Peterbilt customer service at 1-940-591-4220. PACCAR's number for this recall is 20PBF.
Power Train:axle Assembly 2020-08-26 · campaign 20V506000 · 1,097 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2020-2021 Peterbilt 348, 365, 367, 389, 520, 567 and Kenworth T800, T880, W900, W990 vehicles equipped with Watson and Chalin steerable lift axle suspension systems (model SL2065). The axles may have lower rear pivot bolts that are not long enough to sufficiently engage the locking feature of the corresponding nuts.
Risk: The short screws can cause the hardware to separate from the suspension system and become road hazards, increasing the risk of a crash and/or injury.
Fix: PACCAR will notify owners, and dealers will inspect suspect chassis and replace the pivot bolts, as necessary, free of charge. The recall began September 29, 2020. Owners may contact Kenworth customer service at 1-425-828-5888 and Peterbilt customer service at 1-940-591-4220. PACCAR's numbers for this recall is 20PBE and 20KWC.
Steering:electric Power Assist System 2020-07-24 · campaign 20V429000 · 239 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2020 Peterbilt 520 vehicles. Incorrect bolts may have been used to secure the steering assist cylinder bracket, possibly allowing the bolts to loosen.
Risk: Loose bolts may cause the bracket to flex or break, potentially damaging adjacent components or locking up the steering, increasing the risk of crash.
Fix: PACCAR will notify owners, and dealers will install hardware with thread adhesive and replace any components damaged by the improperly secured steer assist bracket, free of charge. The recall began August 17, 2020. Owners may contact PACCAR customer service at 1-425-828-5888. PACCAR's number for this recall is 20PBD.
Service Brakes, Air 2020-03-04 · campaign 20V132000 · 233 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2016-2020 Peterbilt 320 and 520 vehicles with dual foot valves and a liftable tag or tri-drive rear axles. The rear brake signal hose may be missing a quick release valve, possibly causing a delay in their brake release timing. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 121, "Air Disc Brakes."
Risk: A delayed brake release may increase the risk of crash.
Fix: PACCAR will notify owners, and dealers will check the vehicles for a quick release valve, installing one as necessary, free of charge. The recall began March 24, 2020. Owners may contact PACCAR customer service at 1-940-591-4220. PACCAR's number for this recall is 20PBB.
Power Train:axle Assembly:axle Shaft 2019-12-19 · campaign 19V911000 · 148 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2020 Kenworth T800, T880 and W990 and Peterbilt 348, 367, 389, 520, and 567 vehicles. The forward rear axle output shafts may have been improperly heat treated during manufacturing, possibly resulting in the shafts fracturing.
Risk: If the rear axle output shaft fractures, the shaft or interaxle driveline could detach and become a road hazard, increasing the risk of a crash.
Fix: PACCAR will notify owners, and dealers will inspect and replace the output shafts, as necessary, free of charge. The recall began February 19, 2020. Owners may contact Kenworth customer service at 1-425-828-5888 or Peterbilt customer service at 1-940-591-4220. PACCAR's numbers for this recall are 19KWE and 19PBG.
Exterior Lighting:turn Signal 2019-06-14 · campaign 19V452000 · 343 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 1990-2020 Peterbilt 320 and 520 vehicles built with specific amber rear turn signals. The turn signals may also light up with the stop/tail lights when the brakes are applied. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices, and Associated Equipment."
Risk: Rear Turn signals that illuminate at the same time as the brake lights may create confusion and impair the effectiveness of the brake lights, increasing the risk of a crash.
Fix: PACCAR will notify owners, and for trucks with rear amber lights, dealers will add a jumper harness between the chassis electrical harness and amber tail lights, free of charge. The recall began August 1, 2019. Owners may contact PACCAR customer service at 1-940-591-4220. PACCAR's number for this recall is 19PBC.
Engine 2019-04-09 · campaign 19V282000 · 5,051 vehicles
Defect: PACCAR Incorporated (PACCAR) is recalling certain 2017-2020 Peterbilt 520 vehicles. Due to undersized wires, the connector between the cab power harness and the power distribution center (PDC) harness may overheat and melt, possibly resulting in an engine shutdown.
Risk: An unexpected engine shut down can increase the risk of a crash.
Fix: PACCAR will notify owners, and dealers will replace the main power wire to the PDC with a wire of the correct size, free of charge. The recall began August 6, 2019. Owners may contact PACCAR customer service at 1-918-259-3258. PACCAR's number for this recall is 19PBB.
Service bulletins (51)
Technical service bulletins are repair instructions manufacturers send dealers for known issues. Unlike recalls, the fix is not automatically free — but naming the bulletin at the service desk can save diagnosis time and support goodwill repairs.
Engine 2026-09-11 · P001 · Service Bulletin/Repair Instructions
"kenworth: dealers should check the chassis list and sir weekly for vin changes. 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."
Engine 2026-08-13 · 43-088 · Service Bulletin/Repair Instructions
the procedure has been updated to include additional steps for verifying the software level on the vehicle electronic control unit (vecu2) and digital display (dd). steps have also been added to the paccar common rail injection 2 (pci2) software verification.
Engine 2026-07-21 · 43-088 · Service Bulletin/Repair Instructions
this optional software update is now available for chassis equipped with emy 2021b-2023 paccar mx-11 and mx-13 engines. 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 recentl
Engine 2026-07-07 · 43-088 · Service Bulletin/Repair Instructions
"the software is not yet available. the bulletin will be updated when more information is available."
Engine 2026-06-29 · 43-088 · Service Bulletin/Repair Instructions
"an optional software update will be available on 07/06/2026 for chassis equipped with emy 2021b-2023paccar mx-11 and mx-13 engines. 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
Engine 2026-04-01 · E326 · Emissions
epa17-24 mx fuel injector connector - this bulletin has been revised to include all epa17-24 and carb24 paccar mx engines.
Showing the 6 most recent of 51 bulletins. Search all of them free at nhtsa.gov.
What owners report
2021-08-02 · Service Brakes“truck was brought in because driver heard a grinding noise. mechanic inspected and found that the front disc brake pads and separated from the backing. truck was thought to still be under warranty and was then taken to dealership for repairs.…”
2021-08-02 · Service Brakes“this one was taken in after the first one also for inspection by dealer. issue wasn't as severe due to lower mileage and use. i believe the pads were just changed as a precaution, i don't believe they had started to separate.…”
2021-08-02 · Service Brakes“after issue with first truck dealership asked to bring in others to be inspected and found same issue with them. front brake pads were separating from backing. this truck had less mileage so damage not as severe.…”
Excerpts of consumer complaints filed with NHTSA, lightly truncated. They are owner statements, not verified findings.