Service bulletins for the 2020 Peterbilt 520
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
52 on file from NHTSA, as of 2026-10-19.
By type
By component
By trouble code
By topic
| 34-077 | 2019-05-13. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT:ELECTRICAL. Information Only: Proper instructions for closure of power distribution box cover to prevent corrosion. |
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| 34-074 | 2019-05-13. Service bulletin. ELECTRICAL SYSTEM. Non Safety Campaign: Vehicles were built with a 5 bolt supply wire for the air dryer pressure sensor that is no longer required with current architecture. If left in place, a fault code P1644 may be set. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.