I was driving on a freeway when suddenly my truck lost all power. I managed to coast to a safe spot to park. I immediately opened hood and started troubleshooting. Left key on so I'd know if power came back on. After about 10 minutes of moving wires gently I found the issue. A power wire plug connected to cab. I wiggled it and everything worked again. Messed up again and again, that day. Vehicle was still warrantied, but shops didn't have time to get it in. Finally I found a temporary solution. If I hold wire sideways after cutting zip ties it wouldn't mess up again. Shop said they must replace entire wire. Totally a safety issue. Could have resulted in bad situations if it happened at the wrong time.
The worst 2021 Peterbilt 579 problems
Ranked by number of owner complaints. Mileage and cost come from what owners wrote.
- Electrical1
Problems by type
Tap a problem to see which part fails, at what mileage and in which other years.
- Electrical1
Recalls 9
Electrical system: software
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2021-2025 Peterbilt and Kenworth vehicles, equipped with Bendix EC80 Advanced Electronic Control Units (ECU). Please see the recall report for a complete list of models. Electrical noise and low signal to the power line carrier may cause the ECU to incorrectly process commands or stop functioning.
- Risk
- Safety systems that depend on the ECU (Automatic Traction Control, ABS, Electronic Stability Control, Active Cruise Control, and Collison Mitigation System) may not function properly or at all, increasing the risk of a crash.
- Remedy
- Dealers will reprogram the ECU software, free of charge. Owner notification letters were mailed February 3, 2025. Owners may contact Kenworth's customer service at 1‑425‑828‑5888 and Peterbilt's customer service at 1‑940‑591‑4220. PACCAR's numbers for this recall are 24KWL and 24PBL.
Recall number 24V915000 · Recall details
Power train: automatic transmission: lever and linkage: column shift
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2021-2024 Peterbilt 365, 367, 389, 535, 536, 537, 548, 567, 579, and 2021-2025 Kenworth T180, T280, T380, T480, T680, T880 and W990 trucks. The right-hand gear shifter stalk connectors may have been improperly crimped, resulting in a loss of communication.
- Risk
- A loss of communication between the gear shifter and the transmission may result in the vehicle becoming disabled after coming to a stop, increasing the risk of a crash.
- Remedy
- Dealers will inspect and replace the gear shifter assembly as necessary, free of charge. Owner letters were mailed December 15, 2025, then phased after that. 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 24PBE and 24KWE.
Recall number 24V190000 · Recall details
Fuel system, diesel: storage: tank assembly
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2021-2024 Peterbilt 579 and 567 trucks. The U-bolts that attach the air tank to the chassis may contact the fuel tank and over time, wear a hole in the tank.
- Risk
- A punctured fuel tank can leak fuel, increasing the risk of a fire.
- Remedy
- Dealers will inspect and trim the U-bolts, and replace the fuel tank as necessary, free of charge. Owner notification letters were mailed November 3, 2023. Owners may contact Peterbilt's customer service at 1‑940‑591‑4220. PACCAR's number for this recall is 23PBH.
Recall number 23V653000 · Recall details
Electrical system
- What is wrong
- PACCAR, Incorporated (PACCAR) is recalling certain 2021-2023 Peterbilt 579 vehicles equipped with MX-13 engines and 160-amp alternators. A fastener on the front spring bracket may have been installed with the head on the outside of the frame rail, which can chafe and damage the alternator positive cable.
- Risk
- A damaged alternator cable increases the risk of a fire.
- Remedy
- Dealers will replace the frame fastener and secure the alternator cable, free of charge. Owner notification letters are expected to be mailed August 11, 2023. Owners may contact Peterbilt's customer service at 1‑940‑591‑4220. PACCAR's number for this recall is 23PBD.
Recall number 23V423000 · Recall details
Electrical system: wiring
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2016-2022 Peterbilt 567, 579, 2021-2022 Peterbilt 536, 2017-2021 Kenworth T880, 2016-2022 Kenworth T680, 2018-2020 Kenworth T440, 2020 Kenworth T270, and 2021 Kenworth T280 vehicles. The methane detection system will not function if the system loses power.
- Risk
- The operator may be unaware of a system malfunction or the presence of excessive methane levels, increasing the risk of injury or fire.
- Remedy
- Dealers will re-wire the warning alarm, free of charge. Owner notification letters were mailed December 1, 2022. Owners may contact Peterbilt customer service at 1‑940‑591‑4220, and Kenworth customer service at 1‑425‑828‑5888. PACCAR's numbers for this recall are 21KWH and 21PBN.
Recall number 21V00N000 · Recall details
Electrical system: software
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2019-2022 Kenworth T880, W990, Peterbilt 567, 579, 389, and 2022 Peterbilt 536, 537 wrecker and auto hauler vehicles. The work brake (winch brake) may unintentionally disengage the service brakes during winching operations, causing the vehicle to roll.
- Risk
- Unintended vehicle movement can increase the risk of a crash or injury.
- Remedy
- Dealers will update the vehicle software, free of charge. Owner notification letters were mailed on January 3, 2022. 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 21KWG and 21PBM.
Recall number 21V906000 · Recall details
Service brakes, hydraulic: foundation components: hoses, lines/piping, and fittings
- What is wrong
- PACCAR, Inc. (PACCAR) is recalling certain 2021-2022 Peterbilt 367, 389, 567, and 579 vehicles. The cross member mounted Hill Start Assist valve assembly may have insufficient clearance to the rear axle, causing damage to the rear brake hose and loss of the rear brake signal.
- Risk
- If loss of the rear brake signal occurs, the vehicle could experience reduced rear braking capability or loss of brakes to the rear axle(s), increasing the risk of a crash.
- Remedy
- Dealers will inspect for clearance and re-work the assembly to conform with an updated design, free of charge. Interim owner notification letters were mailed on September 24, 2021. Owner notification letters were mailed on March 11, 2022. Owners may contact PACCAR's customer service at 1‑940‑591‑4220 (Peterbilt). PACCAR's number for this recall is 21PBJ.
Recall number 21V648000 · Recall details
Service brakes, air: disc: chamber
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2021 Peterbilt 348 and 579 vehicles. The spring brake chamber may have been assembled with incorrect springs that were out of specification, which may cause the pressure plate to shift.
- Risk
- The pressure plate may tear the diaphragm, causing a loss of air pressure and increasing the risk of a crash.
- Remedy
- Dealers will replace brake chambers, free of charge. Owner notification letters were mailed on July 9, 2021. Owners may contact PACCAR (Peterbilt) customer service at 1‑940‑591‑4220. PACCAR's number for this recall is 21PBE.
Recall number 21V328000 · Recall details
Engine
- What is wrong
- PACCAR Incorporated (PACCAR) is recalling certain 2021-2022 Kenworth T680, T880, W990, T800, W900 and Peterbilt 579, 567, 389, 367 vehicles equipped with a Cummins X15 engine. The capscrews that attach the flywheel to the crankshaft may have been improperly torqued, allowing the flywheel to detach.
- Risk
- A detached flywheel can cause loss of drive power, increasing the risk of a crash. Additionally, driveline pieces may be ejected from the engine compartment, increasing the risk of injury.
- Remedy
- PACCAR will notify owners, and dealers will properly torque the capscrews and the engine will also be inspected for damage and, if necessary, repaired, free of charge. The recall began on March 29, 2021. 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 21KWA and 21PBB.
Recall number 21V080000 · Recall details
Technical service bulletins for the 2021 Peterbilt 579 119
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- "KW & PB 14 fuel injector part numbers (seven for MX-11 and seven for MX-13 engines) have been added to...
- 7/700 Service Agreement
- The new 2.1m day cab lift tools, a Level 3 mandatory tool, are now available to order.
- Certain chassis equipped with an engine model year 2019
- This optional software update is expected to be available after 10/30/2026 for chassis equipped with EMY...
- "Kenworth: Dealers should check the chassis list and SIR weekly for VIN changes
- An exhaust manifold slip joint seal kit is now available for EPA 2017-2024 PACCAR MX-13 engines.
- The procedure has been updated to include additional steps for verifying the software level on the vehicle...
- The verbiage in the Introduction section has been updated.
- 235 chassis have been removed from the chassis list and unflagged in PRWS due to expiration of applicable...
What 2021 Peterbilt 579 owners say
Most recent owner complaints, unedited.
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Questions about the 2021 Peterbilt 579
Is the 2021 Peterbilt 579 reliable?
Owners have filed 1 complaint about the 2021 Peterbilt 579, fewer than a typical 579 model year.
What is the most common problem with the 2021 Peterbilt 579?
Electrical system, with 1 complaint.
How many recalls does the 2021 Peterbilt 579 have?
9 recalls, covering electrical system, power train and fuel system, diesel.
Was there a recall on the 2021 Peterbilt 579 electrical?
Yes, 4 recalls: 24V915000, 23V423000, 21V00N000. Check your VIN to see if your car still needs the free repair.
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